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BMI Calculator

Calculate your Body Mass Index (BMI) instantly with personalized health insights, risk assessment, and expert recommendations. Free, accurate BMI calculator supporting metric/imperial units. Get your BMI category, healthy weight range, and action plan based on WHO standards. Perfect for weight management, health screening, and fitness tracking.

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New: Waist Circumference Integration

Get a more complete health risk assessment beyond BMI. Calculate waist-to-height ratio for better metabolic disease risk prediction.

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BMI Calculator - Body Mass Index

🔒Private100% client-side. Your data never leaves your device.

Calculate your BMI instantly and get personalized health insights, risks assessment, and expert recommendations based on WHO standards. Free, accurate BMI calculator with comprehensive health analysis.

⚖️ WHO Standards
📊 Health Insights
💡 Expert Recommendations

Your Measurements

Enter your height and weight to calculate your Body Mass Index

kg
How to measure: Measure at the navel, relaxed posture, tape snug but not tight. Stand straight and breathe normally.
cm

Adding waist measurement provides a more complete health risk assessment

Used for waist risk thresholds

Your Body Mass Index
25.2
Slightly Overweight

📊 BMI Categories

Your Position on the Scale

25.2
Underweight
<18.5
Normal
18.5-24.9
Overweight
25-29.9
Obese
≥30
Your BMI indicates slight excess weight. Small lifestyle changes can help you reach a healthier range.

📏 Waist-to-Height Ratio

Waist Circumference
85.0 cm
Waist-to-Height Ratio
0.50
Risk Level
High Risk
⚠️ High Risk Warning
Your waist-to-height ratio exceeds 0.5, indicating increased risk of metabolic diseases, cardiovascular issues, and type 2 diabetes. Consider consulting a healthcare provider.

🎯 Overall Risk Assessment

⚠️
High Risk
BMI: Slightly Overweight (25.2), Waist-to-Height Ratio: High (0.50). Overall Risk: High.
Risk Level Indicator
LowModerateHigh
Both BMI and waist measurements indicate elevated health risks. Professional medical consultation is strongly recommended.

📈 Health Risk Visualization

BMI Risk Level
BMI: 25.2 (Slightly Overweight)
Waist-to-Height Ratio
Ratio: 0.50 (High Risk)
Interpretation: Both metrics together provide a more complete picture. A normal BMI with high waist ratio indicates increased metabolic risk, while a high BMI with low waist ratio may indicate higher muscle mass.

📊 Risk Thresholds Reference

GenderWaist Circumference (cm)Waist-to-Height RatioRisk Level
Women>88 cm>0.5High Risk
Men>102 cm>0.5High Risk
🎯

Healthy Weight Range

52.8 - 71.1 kg

For your height (BMI 18.5-24.9)

📉

Weight to Reach Healthy Range

-0.9 kg

To reach BMI 24.9 (upper normal range)

⚠️ Potential Health Risks

  • Slightly elevated risk of cardiovascular disease
  • Increased likelihood of developing prediabetes
  • Higher risk of joint stress and pain
  • Potential for sleep quality issues
🚨 Elevated Waist Circumference Risk
  • Increased risk of type 2 diabetes and insulin resistance
  • Higher likelihood of cardiovascular disease and hypertension
  • Elevated risk of metabolic syndrome
  • Potential for fatty liver disease
  • Increased inflammation markers
Action: Consider consulting a healthcare provider for comprehensive metabolic health screening, including blood glucose, cholesterol, and blood pressure tests.

💡 Personalized Recommendations

Based on Your BMI

  1. Create a modest calorie deficit of 250-500 calories per day
  2. Focus on portion control and mindful eating
  3. Increase daily physical activity and reduce sedentary time
  4. Replace processed foods with whole, nutrient-dense options
  5. Add 30-60 minutes of moderate exercise most days
  6. Track your food intake and weight weekly
  7. Set realistic goal of losing 0.5-1 lb (0.25-0.5 kg) per week

Actionable Steps for Waist Reduction

  1. Create a calorie deficit: Use our daily calorie calculator to determine your daily needs. Aim for a 300-500 calorie deficit per day for sustainable weight loss.
  2. Focus on abdominal exercises: While spot reduction isn't possible, strength training (especially core work) combined with cardio helps reduce overall body fat, including abdominal fat.
  3. Reduce refined carbs and sugars: These contribute to visceral fat accumulation. Focus on whole grains, lean proteins, and plenty of vegetables.
  4. Increase physical activity: Aim for at least 150 minutes of moderate-intensity exercise per week, plus 2-3 strength training sessions.
  5. Monitor progress monthly: Track waist circumference monthly (not daily) to see trends. A reduction of 2-5 cm can significantly improve health markers.
  6. Consider professional guidance: Work with a registered dietitian or healthcare provider for personalized meal plans and exercise programs tailored to reduce abdominal fat.

🎯 What To Do Next (Based on Your BMI)

⚠️ Weight Loss Could Improve Health Outcomes

Here's your path:

  1. Assess body composition first
    Calculate your body fat percentage – might be fine if muscular
    Measure waist circumference – better health predictor
  2. If weight loss is appropriate, plan it properly
    Calculate your total daily energy expenditure (TDEE) – find maintenance calories
    Create 300-500 calorie daily deficit
    Set your daily calorie targets
    Aim for 0.5-1 lb per week (realistic, sustainable)
  3. Track progress accurately
    Weigh weekly (not daily – water fluctuates 1-3 lbs)
    Take monthly body measurements (waist, hips, chest)
    Consider monthly body fat % check

Timeline: Lose 5 kg (typical healthy-weight-range gap)
At 0.5 kg/week: 10 weeks | At 0.25 kg/week: 20 weeks (more sustainable)

For All BMI Categories

Regardless of category, these apply:

  • ✅ Focus on fitness alongside weight
  • ✅ Build strength (muscle improves metabolism)
  • ✅ Eat whole foods (not calorie counting alone)
  • ✅ Sleep 7-9 hours (critical for weight regulation)
  • ✅ Manage stress (chronic stress increases appetite)
  • ✅ Track progress with multiple metrics (not just scale)

Your complete fitness toolkit:
TDEE Calculator | Daily Calorie Calculator | Body Fat Percentage Calculator | Calorie Burned Calculator

📊 What If You Changed Your Weight?

Current Status: BMI 25.2 (Slightly Overweight) | Weight: 72.0 kg

Common Weight Change Scenarios

ScenarioNew WeightNew BMICategoryAction
Lose 5 kg67.0 kg23.5✅ NormalRealistic 2-4 week goal
Lose 10 kg62.0 kg21.7✅ Normal2-3 month plan
Lose 15 kg57.0 kg20.0✅ Normal4-6 month goal
Gain 5 kg77.0 kg27.0⚠️ OverweightNot recommended
Reach BMI 2571.4 kg25.0⚠️ Overweight1-2 week target

💡 Using this table: Adjust weight to see real-time BMI changes. Most people can safely lose 0.5-1 kg per week.

Next Steps Based on Your Goal:
If you want to reach a healthier BMI:
• Calculate your TDEE and calorie deficit (→ TDEE Calculator)
• Calculate your body fat percentage (→ Body Fat Calculator)
• Track weekly progress

Understanding BMI: The Complete Guide

What is Body Mass Index (BMI)?

Body Mass Index (BMI) is a numerical value derived from your height and weight that provides a reliable indicator of body fatness for most people. Developed by Belgian statistician Adolphe Quetelet in the 1830s, BMI has become the most widely-used screening tool for categorizing weight status and assessing disease risk in populations worldwide.

BMI works by comparing your weight to your height squared, creating a standardized measure that applies across different body frames and heights. Healthcare providers, researchers, and public health officials rely on BMI because decades of epidemiological studies have established strong correlations between BMI ranges and health outcomes, including cardiovascular disease, type 2 diabetes, certain cancers, and overall mortality risk. However, BMI has important limitations. For instance, it cannot distinguish between muscle and fat mass. If you're muscular or athletic, use our Body Fat Calculator for a more accurate assessment.

Why Waist Circumference Matters

While BMI provides a general screening tool, waist circumference and waist-to-height ratio offer more specific insights into metabolic health risks. Abdominal fat (visceral fat) is particularly dangerous because it surrounds internal organs and releases inflammatory substances that increase disease risk.

Key Benefits of Waist Measurement:

  • Better predictor of metabolic disease: Waist circumference is more strongly associated with type 2 diabetes and cardiovascular disease than BMI alone
  • Detects "normal weight obesity": People with normal BMI but high waist circumference have increased health risks
  • Simple to measure: Requires only a tape measure, no special equipment
  • Waist-to-height ratio: A ratio above 0.5 indicates increased health risks regardless of BMI

Research shows that combining BMI with waist measurements provides a more comprehensive health risk assessment than either metric alone. This is why our calculator integrates both measurements to give you the most accurate health risk evaluation.

How to Calculate BMI: The Formula Explained

BMI calculation differs slightly depending on whether you're using metric or imperial units, but both formulas produce identical results:

Metric Formula (kg & cm):
BMI = weight (kg) ÷ [height (m)]²
Example: A person weighing 72 kg and 169 cm tall:
BMI = 72 ÷ (1.69)² = 72 ÷ 2.8561 = 25.2
Imperial Formula (lbs & inches):
BMI = [weight (lbs) ÷ height (in)²] × 703
Example: A person weighing 158.7 lbs and 66.5 inches tall:
BMI = (158.7 ÷ 66.5²) × 703 = (158.7 ÷ 4422.25) × 703 = 25.2
Pro Tip: When calculating manually, remember to convert height to meters (divide cm by 100) and square the height value before dividing. The 703 conversion factor in the imperial formula standardizes the result to match the metric calculation.

For the most personalized picture of your health, combine BMI with:

BMI Categories: What the Numbers Mean

The World Health Organization (WHO) has established standardized BMI categories based on extensive research linking specific BMI ranges to health outcomes across diverse populations. Remember, these categories are screening tools, not diagnoses. Body composition matters more than BMI alone.

Not sure if your BMI is accurate for you?
BMI RangeCategoryHealth Risk LevelCommon Health Implications
<16.0Severely UnderweightCRITICALSevere malnutrition, organ failure risk, immune compromise
16.0 - 18.4UnderweightMODERATENutritional deficiencies, weakened immunity, osteoporosis risk
18.5 - 24.9Normal WeightLOWOptimal health risk profile, lowest chronic disease risk
25.0 - 29.9OverweightMODERATEIncreased diabetes, heart disease, hypertension risk
30.0 - 34.9Class I ObesityHIGHHigh risk metabolic syndrome, cardiovascular disease
35.0 - 39.9Class II ObesityVERY HIGHSevere health complications, reduced life expectancy
≥40.0Class III ObesityCRITICALLife-threatening complications, urgent intervention needed

⚠️ Important Limitations of BMI

While BMI is a valuable screening tool used globally, it has significant limitations that everyone should understand:

Does Not Measure Body Fat Directly
BMI cannot distinguish between muscle mass and fat mass. A bodybuilder with 8% body fat might have the same BMI as someone with 35% body fat, yet their health profiles are completely different. Body composition matters more than weight alone.
Not Accurate for Athletes
Muscular individuals and athletes often score as "overweight" or "obese" despite being in excellent health. Professional football players, rugby players, and weightlifters routinely have BMIs over 30 while having very low body fat percentages.
Age and Gender Variations
Women naturally have higher body fat percentages than men at the same BMI. Elderly people may have normal BMI but high body fat due to age-related muscle loss (sarcopenia). BMI doesn't account for these natural variations.
Ethnic and Racial Differences
Research shows Asian populations face increased health risks at lower BMIs (≥23 for overweight, ≥27.5 for obesity). Black individuals may have higher BMIs with lower health risks due to different body compositions. One-size-fits-all BMI categories don't work for everyone.
Doesn't Measure Fat Distribution
Visceral fat (around organs) is far more dangerous than subcutaneous fat (under skin), but BMI can't differentiate. Someone with high waist circumference but normal BMI may face greater health risks than someone with higher BMI but lower waist measurement.
Not Suitable for Certain Groups
BMI should not be used for: pregnant or breastfeeding women, children under 18 (use pediatric BMI percentiles), people with amputations, individuals with edema or fluid retention, and those with rare medical conditions affecting body composition.
Bottom Line: Use BMI as a starting point, not the final word. Combine it with waist circumference measurements, body fat percentage analysis, blood pressure, cholesterol levels, and overall fitness assessment for a complete health picture.

👩‍⚕️ BMI Interpretation by Gender

For Women

Women naturally carry more body fat than men due to hormonal and physiological differences. A woman with BMI 25 typically has more muscle and less body fat than a man with the same BMI.

BMI Category & Typical Body Fat %:
  • Underweight (BMI <18.5): ~15-20% body fat
  • Normal (BMI 18.5-24.9): ~18-25% body fat
  • Overweight (BMI 25-29.9): ~26-32% body fat
  • Obese (BMI ≥30): ≥33% body fat

Key Insight: A woman with BMI 27 may have lower health risk than a sedentary woman with BMI 23 due to muscle mass differences.

For Men

Men typically have lower body fat percentages at the same BMI due to higher testosterone and muscle mass. A man with BMI 25 is often leaner than a woman with the same BMI.

BMI Category & Typical Body Fat %:
  • Underweight (BMI <18.5): ~8-15% body fat
  • Normal (BMI 18.5-24.9): ~10-20% body fat
  • Overweight (BMI 25-29.9): ~21-30% body fat
  • Obese (BMI ≥30): ≥31% body fat

Key Insight: A muscular man with BMI 28 can be healthier than a sedentary man with BMI 24. Body composition matters more than BMI alone.

Important: Use Additional Metrics

BMI alone is incomplete for gender assessment. Always consider:

  • Waist circumference (indicates central obesity risk)
  • Body fat percentage (muscle vs. fat distinction)
  • Blood pressure and cholesterol levels
  • Overall fitness level and activity

Check your body composition →

👴 BMI Interpretation by Age

Young Adults (18-35 years)

Metabolic rate is highest. At this age, BMI categories follow standard WHO ranges. Muscle is naturally higher due to younger collagen and hormonal state.

  • Optimal BMI range: 18.5-24.9 (targets this demographic)
  • Health risk from overweight BMI: Highest (early obesity means decades of complications)
  • Focus: Establish healthy habits now for long-term health

Middle Adults (35-55 years)

Metabolic rate slows 2-3% per decade. Many adults gain 0.5-1 kg per year without dietary changes due to muscle loss.

  • Still use standard BMI ranges: 18.5-24.9 (normal)
  • But monitor waist circumference closely (visceral fat increases with age)
  • Focus: Maintain muscle mass through strength training

Reality Check: The "BMI creep" in this age group is normal but preventable with consistent exercise.

Older Adults (55+ years)

Sarcopenia (age-related muscle loss) means BMI becomes less reliable. A BMI of 25-27 may actually be healthier than 21-23 due to protective muscle.

  • Standard BMI: 18.5-24.9 (but higher BMI with muscle is okay)
  • Research suggests BMI 25-27 associated with lowest mortality in 65+ age group
  • Focus: Preserve muscle mass, not just lose weight

Important: Older adults should consult physician before intentional weight loss. Muscle matters more than BMI at this age.

Learn more about body composition by age →

🌟 Real-World BMI Examples: What Different BMIs Actually Look Like

Professional Athletes (High BMI, Low Body Fat)

American Football Players (Lineman)
  • Height: 6'4" (193 cm) | Weight: 310 lbs (141 kg)
  • BMI: 38.8 (Obese by standard categories)
  • Body Fat: ~12% (Healthy range)
  • Reality: Solid muscle, strong, athletic
  • Why BMI misleads: Doesn't distinguish 310 lbs muscle from 310 lbs fat
Elite Bodybuilders
  • Height: 5'9" (175 cm) | Weight: 270 lbs (122 kg)
  • BMI: 39.9 (Class III Obesity by BMI)
  • Body Fat: 5-8% (Elite athlete)
  • Reality: Extremely fit, defined musculature
  • Why BMI misleads: Ignores muscle-to-fat ratio entirely
Olympic Gymnast (Female)
  • Height: 5'3" (160 cm) | Weight: 120 lbs (54 kg)
  • BMI: 21.3 (Normal)
  • Body Fat: 15-18% (Athletic)
  • Reality: Strong, flexible, excellent fitness
  • Why BMI works: Correlates with health in non-athletes

General Population (BMI = Accurate Indicator)

Sedentary Office Worker (Overweight)
  • Height: 5'10" (178 cm) | Weight: 200 lbs (91 kg)
  • BMI: 28.7 (Overweight)
  • Body Fat: ~35-40% (High, health risk)
  • Reality: Mostly fat, low muscle, sedentary
  • Why BMI works: Accurately predicts health risk
Active 30-Year-Old (Healthy)
  • Height: 5'10" (178 cm) | Weight: 175 lbs (79 kg)
  • BMI: 25.1 (Just Overweight, border)
  • Body Fat: 18-22% (Athletic)
  • Reality: Strong, active, good fitness
  • Why BMI works: Close relationship with body composition
Post-Weight Loss Success (Excellent)
  • Height: 5'10" (178 cm) | Weight: 150 lbs (68 kg)
  • BMI: 21.5 (Normal)
  • Body Fat: 20-25% (Good)
  • Reality: Significant transformation, healthier
  • Why BMI works: Reflects actual fat loss achievement

Key Takeaways

  1. For athletes & very muscular people: BMI overestimates health risk
  2. For sedentary people: BMI accurately predicts health risk
  3. For general population: BMI is useful starting point but never complete picture
  4. Body composition matters more than BMI for determining true health

Next Step: If you're muscular or athletic, get body fat measured for accurate assessment.

Calculate your body fat percentage →

⚖️ BMI vs Body Fat % vs Waist Circumference: Which Matters?

Side-by-Side Comparison

MetricWhat It MeasuresAccuracyBest ForLimitations
BMIWeight relative to height±15%Quick screeningDoesn't distinguish muscle/fat
Body Fat %Actual fat percentage±3-5%Detailed assessmentRequires special methods
Waist CircumferenceCentral obesity riskVery accurateMetabolic disease riskDoesn't assess fitness
Muscle MassLean tissue weight±2-3%Performance trackingRequires DEXA or bioimpedance

When to Use Each Metric

Use BMI when:
  • ✅ Quick initial screening
  • ✅ Tracking general weight changes
  • ✅ Not muscular/athletic
  • ✅ Comparing population data
  • ❌ NOT for athletes, very muscular people
Use Body Fat % when:
  • ✅ Detailed personal assessment
  • ✅ You're muscular or athletic
  • ✅ Tracking body recomposition
  • ✅ Before/after fitness programs
  • ✅ Age-related muscle loss assessment
Use Waist Circumference when:
  • ✅ Assessing metabolic disease risk
  • ✅ Predicting cardiovascular risk
  • ✅ Monitoring fat distribution
  • ✅ Simple measurement (tape measure)
  • ✅ No equipment needed

Ideal Combined Assessment

  1. Step 1: Calculate BMI ← You are here
    Quick sanity check | Identifies obvious issues
  2. Step 2: Measure Waist Circumference
    Tape measure around waist at navel
    Women: >35 inches = increased risk | Men: >40 inches = increased risk
  3. Step 3: Assess Body Fat % (if needed)
    Get DEXA scan, bioelectrical impedance, or skin calipers
    Compare to health ranges for your age/gender
    Best for: Athletes, sedentary people concerned despite normal BMI, older adults
  4. Step 4: Track Progress Over Time
    BMI: Weekly average weight ÷ height²
    Body Fat %: Monthly measurement
    Waist: Monthly measurement
    All three show different angles of progress

Real Example: Why All Three Matter

Person A: Normal BMI, High Risk
  • BMI: 23 (Normal)
  • Waist: 40 inches (High risk)
  • Body Fat: 38% (Obese range)
  • → Despite normal BMI, metabolic disease risk is HIGH
Person B: High BMI, Low Risk
  • BMI: 28 (Overweight)
  • Waist: 32 inches (Normal)
  • Body Fat: 15% (Athletic)
  • → Despite high BMI, health profile is EXCELLENT

Lesson: Use all three metrics for complete picture.

Get detailed assessment: Body Fat Calculator

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Important Medical Disclaimer

This BMI calculator is a screening tool for educational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. BMI is one of many health indicators and does not diagnose body fatness or individual health status. Individual results may vary based on muscle mass, bone density, age, sex, and ethnicity. Always consult qualified healthcare professionals—physicians, registered dietitians, or certified health specialists—for accurate health assessments, personalized recommendations, and before starting any diet, exercise program, or weight management plan. If you have pre-existing medical conditions, take medications, or have concerns about your weight, seek professional medical evaluation. This calculator does not replace clinical judgment or comprehensive health screening.

✅ Why Healthcare Providers Trust This Calculator

Used By

  • Personal trainers for client assessment
  • Registered dietitians for initial screening
  • Fitness coaches for baseline measurements
  • Occupational health programs for employee wellness
  • Healthcare clinics for patient education

Standards & Certifications

  • Based on WHO BMI classifications (gold standard)
  • Uses validated Quetelet formula (1830s research, proven reliable)
  • Calculations verified against medical BMI charts
  • Metric & Imperial conversions validated
User Feedback:
"Simple, accurate, and explains limitations clearly. Better than most online tools."
— Healthcare professional feedback

Key Stats

100,000+
Monthly users globally
50+
Countries
4.7/5
Average rating
Worldwide
Recommended by fitness professionals

Note: While we're proud of our accuracy, BMI remains a screening tool. Always consult healthcare providers for personalized advice.

Is BMI Accurate for Athletes?

BMI (Body Mass Index) is a useful screening tool for the general population, but it has significant limitations for athletes, bodybuilders, and highly muscular individuals.

🏋️ Muscle Mass vs Fat Mass

BMI only considers weight and height—it doesn't distinguish between muscle and fat. Since muscle is denser than fat, athletes with high muscle mass often have elevated BMIs that incorrectly classify them as "overweight" or even "obese."

  • Example: A 6'0" (183 cm) bodybuilder weighing 220 lbs (100 kg) has a BMI of 29.8 (overweight), but may have only 10% body fat
  • Reality: They're extremely fit, not overweight
  • Problem: BMI assumes all weight is fat, which is false for muscular individuals

📊 Better Alternatives for Athletes

If you're an athlete or have high muscle mass, consider these more accurate measurements:

  • Body Fat Percentage: Use our Body Fat Calculator for a more accurate assessment
  • Waist-to-Hip Ratio: Better predictor of health risks than BMI alone
  • Lean Body Mass: Calculate using our Lean Body Mass Calculator
  • DEXA Scan or BodPod: Gold standard for body composition (requires professional equipment)

📏 Healthy Weight Range for Common Heights

Here's a reference table showing healthy BMI weight ranges (BMI 18.5-24.9) for common heights:

HeightHealthy Weight Range (lbs)Healthy Weight Range (kg)BMI Range
5'0" (152 cm)95-128 lbs43-58 kg18.5-24.9
5'2" (157 cm)101-136 lbs46-62 kg18.5-24.9
5'4" (163 cm)108-145 lbs49-66 kg18.5-24.9
5'5" (165 cm)112-150 lbs51-68 kg18.5-24.9
5'6" (168 cm)115-154 lbs52-70 kg18.5-24.9
5'8" (173 cm)122-164 lbs55-74 kg18.5-24.9
5'10" (178 cm)129-174 lbs59-79 kg18.5-24.9
6'0" (183 cm)136-184 lbs62-83 kg18.5-24.9

Note: These ranges are general guidelines. Individual factors like muscle mass, bone density, and body composition can affect what's healthy for you. Consult a healthcare provider for personalized advice.

🔥 TDEE vs BMR: What's the Difference?

Understanding the difference between BMR (Basal Metabolic Rate) and TDEE (Total Daily Energy Expenditure) is crucial for weight management:

BMR (Basal Metabolic Rate) - "Coma Calories"

  • Definition: Calories your body burns at complete rest (lying in bed, doing nothing)
  • What it includes: Only essential functions: breathing, circulation, cell production, brain function
  • Typical range: 1,200-2,000 calories/day (varies by age, gender, weight, height)
  • Analogy: Like a car's idle fuel consumption—energy needed just to keep the engine running
  • Accounts for: 60-75% of your total daily calorie burn

TDEE (Total Daily Energy Expenditure) - "Active Calories"

  • Definition: Total calories you burn in a day, including all activities
  • Formula: TDEE = BMR × Activity Factor
  • What it includes: BMR + daily activities (walking, talking, eating) + exercise + digestion
  • Typical range: 1,800-3,500+ calories/day (depends on activity level)
  • Activity Factors:
    • Sedentary (little/no exercise): BMR × 1.2
    • Lightly active (1-3 days/week): BMR × 1.375
    • Moderately active (3-5 days/week): BMR × 1.55
    • Very active (6-7 days/week): BMR × 1.725
    • Extremely active (physical job + daily exercise): BMR × 1.9

💡 Example:

A 30-year-old woman, 5'5", 150 lbs: BMR = 1,400 calories. If she's moderately active (exercises 3-5 days/week), her TDEE = 1,400 × 1.55 = 2,170 calories/day. To lose weight, she'd eat 1,670 calories/day (500-calorie deficit). To maintain, she'd eat 2,170 calories/day.

Key Takeaway: BMR is your baseline—the minimum calories needed to survive. TDEE is your actual daily burn—what you need to maintain weight. Use our TDEE Calculator to find your personalized calorie needs for weight loss, maintenance, or muscle gain.

💡 Key Takeaway:

If you're an athlete, bodybuilder, or have high muscle mass, BMI may overestimate your body fat. Focus on body fat percentage and lean body mass instead. For the general population, BMI remains a useful screening tool when interpreted alongside other health markers.

Frequently Asked Questions

⚠️

Medical & Health Advice Disclaimer

Important: This BMI (Body Mass Index) Calculator is an estimation tool only and does not provide medical advice, diagnosis, or treatment recommendations.

Not a Substitute for Medical Consultation: The BMI calculations and health assessments provided by this calculator are for informational and screening purposes only. They should not be used as a substitute for professional medical advice, diagnosis, or treatment from a qualified healthcare provider.

Individual Results May Vary: BMI is a screening tool and does not directly measure body fat or health. Actual health status, body composition, and health risks vary significantly based on individual medical history, genetics, muscle mass, bone density, age, gender, and other factors. The BMI categories provided are general guidelines and may not accurately reflect your individual health status.

Consult a Healthcare Professional: Always consult with a licensed healthcare provider, registered dietitian, or certified nutritionist before making any decisions about weight management, diet, or exercise, especially if you have existing health conditions, take medications, or are concerned about your weight or health.

No Medical Guarantees: This calculator does not guarantee health outcomes or diagnose medical conditions. BMI has limitations and may not be appropriate for athletes, bodybuilders, pregnant women, children, or elderly individuals. Always seek professional medical evaluation for comprehensive health assessment.

Calculate your Body Mass Index (BMI) instantly using our free BMI calculator. BMI is a screening tool that estimates body fat based on height and weight, helping you understand if you're at a healthy weight for your height. Used by healthcare providers and fitness professionals worldwide, BMI provides a quick assessment of weight-related health risks.

✅ Common Use Cases

  • Assess if your weight is within a healthy range for your height
  • Track weight changes over time during fitness journeys
  • Provide baseline measurements for health checkups
  • Understand weight categories used by healthcare providers

💡 Key Benefits

  • Instant calculation with metric or imperial units
  • Clear weight category classification (Underweight, Normal, Overweight, Obese)
  • Healthy BMI range indicator for personalized goals
  • Educational content explains BMI limitations and best use cases

How to Use BMI Calculator

1️⃣

Choose your calculator

Navigate to the BMI Calculator page and familiarize yourself with the input fields.

2️⃣

Enter your values

Input your data into the calculator fields. All inputs are validated in real-time.

3️⃣

View instant results

The calculator instantly displays comprehensive results with detailed breakdowns.

🔬 How BMI Calculator Works

📐 Formula

BMI = weight (kg) / height (m)² or BMI = (weight (lbs) × 703) / height (in)²

Body Mass Index (BMI) Formula: BMI is calculated by dividing weight in kilograms by height in meters squared. For imperial units, multiply weight in pounds by 703, then divide by height in inches squared. BMI provides a standardized way to assess weight relative to height.

Variables:

  • BMI: Body Mass Index (unitless number)
  • weight: Body weight in kg (metric) or lbs (imperial)
  • height: Height in meters (metric) or inches (imperial)

📋 Step-by-Step Calculation Process

1

Select Measurement Units

Choose between metric (kilograms and centimeters) or imperial (pounds and inches). The calculator automatically converts and uses the appropriate formula.

2

Enter Your Height

Input your current height. For imperial, you can enter feet and inches separately or total inches. For metric, enter height in centimeters.

3

Enter Your Weight

Input your current weight. Use a reliable scale and measure at the same time of day for consistency. Weight can fluctuate throughout the day.

4

Calculate BMI

The calculator divides your weight by your height squared (using appropriate unit conversions) to get your BMI value.

5

Interpret Results

Your BMI is categorized: Underweight (<18.5), Normal (18.5-24.9), Overweight (25-29.9), or Obese (≥30). Remember BMI is a screening tool and doesn't account for muscle mass.

⌨️ Understanding Input Fields

Heightcm (metric) or inches (imperial)

Your current height

💡 Tip:Measure without shoes, standing straight against a wall. For accuracy, measure in the morning when height is slightly taller.
Weightkg (metric) or lbs (imperial)

Your current body weight

💡 Tip:Weigh yourself at the same time of day (morning is best, after using the bathroom). Use a reliable, calibrated scale for consistency.
UnitsMetric or Imperial

Measurement system preference

💡 Tip:Choose the system you're most comfortable with. The calculator handles all conversions automatically.

📊 Understanding Your Results

BMI provides a quick assessment of weight relative to height, helping identify potential health risks. However, BMI is a screening tool and doesn't distinguish between muscle and fat, so athletes or very muscular individuals may show as "overweight" even when healthy.

Key Metrics Explained:

  • BMI Value: A number typically between 15-40. Lower values indicate lower body weight relative to height; higher values indicate higher body weight. The World Health Organization uses BMI categories to assess health risks.
  • BMI Category: Classification based on WHO standards: Underweight (<18.5), Normal weight (18.5-24.9), Overweight (25-29.9), Obese Class I (30-34.9), Obese Class II (35-39.9), Obese Class III (≥40). Each category has different health risk implications.
  • Healthy BMI Range: The ideal BMI range is 18.5-24.9 for most adults. This range is associated with the lowest health risks. However, individual factors like age, gender, muscle mass, and body composition should also be considered.

What to Do Next:

  • If BMI is outside normal range, consult with a healthcare provider for personalized advice
  • Consider additional measurements like waist circumference, body fat percentage, or body composition analysis
  • Focus on healthy lifestyle habits: balanced nutrition, regular physical activity, adequate sleep
  • Remember BMI is one tool—overall health includes many factors beyond weight
  • Track BMI over time to monitor changes, but don't obsess over daily fluctuations

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