BMI Calculator with Interactive Chart
Calculate your Body Mass Index (BMI) using height and weight with our free BMI calculator. View your results on an interactive BMI chart that shows your BMI category and healthy weight range. Supports both imperial and metric units for accurate BMI calculation.
Your BMI on the Standard Chart
📊 Save results as PDF
Why This BMI Calculator Is Different
I built this BMI calculator because I wanted something that actually shows you where you are on the chart—just like the ones you see at the doctor's office. Most online BMI calculators just give you a number, but that doesn't mean much without context.
📊 Visual BMI Chart
See exactly where your BMI falls on a color-coded chart that matches the standard medical BMI charts. Your position is marked with a clear indicator so you can instantly understand your results.
🔄 Natural Height Input
For imperial units, enter your height the way you actually think about it—feet and inches separately (e.g., 6 ft 2 in). No more mental math to convert to total inches. Metric users can still enter height in centimeters.
📊 Healthy Weight Range Calculator
See exactly what weight range corresponds to a healthy BMI (18.5-24.9) for your height, plus how much weight change would bring you to the ideal BMI of 22.
⚕️ Health Risk Assessment
Get personalized information about potential health risks or benefits associated with your BMI category, based on current medical research.
📱 Clean, Mobile-Friendly Design
No ads, no clutter, no tracking. Just a clean interface that works perfectly on any device and respects your privacy.
📈 Instant Calculations
Your BMI is calculated instantly as soon as you enter your height and weight. No waiting, no page reloads, no unnecessary complexity.
Everything runs locally in your browser—your measurements never leave your device. No accounts, no sign-ups, no data collection.
How BMI Works
Body Mass Index (BMI) is a simple calculation that uses your height and weight to estimate body fat. While it's not perfect, it's a useful screening tool that healthcare professionals use worldwide to assess weight categories that may lead to health problems.
Example: If you weigh 70 kg and are 1.70 m tall (170 cm), your BMI = 70 ÷ (1.70)² = 70 ÷ 2.89 = 24.2
Imperial Formula: BMI = (weight in pounds × 703) ÷ (height in inches)²
Step-by-Step Breakdown
- Step 1: Convert your height to meters (divide cm by 100)
- Step 2: Square your height in meters (multiply it by itself)
- Step 3: Divide your weight in kilograms by the result from step 2
Understanding Your Results
BMI ranges are based on the relationship between body weight and disease and death. The categories established by the World Health Organization are:
- Underweight (BMI < 18.5): May indicate malnutrition, eating disorder, or other health problems
- Normal weight (BMI 18.5 - 24.9): Associated with the lowest health risk
- Overweight (BMI 25 - 29.9): Increased risk of developing health problems
- Obese (BMI ≥ 30): High risk of weight-related health conditions
Real-World BMI Scenarios
Understanding BMI becomes clearer when you see specific examples. Here are realistic scenarios showing how BMI calculations work in practice:
Scenario 1: Average Adult Male
- Height: 5'10" (178 cm)
- Weight: 180 lbs (82 kg)
- BMI: 25.8 (Overweight)
Key Insight: To reach a normal BMI of 24.9, he would need to lose about 6 pounds, bringing his weight to 174 lbs. A BMI of 22 (ideal) would be 154 lbs, requiring a 26-pound weight loss.
Scenario 2: Petite Female
- Height: 5'2" (157 cm)
- Weight: 115 lbs (52 kg)
- BMI: 21.0 (Normal)
Key Insight: Her BMI is in the healthy range. The normal BMI range for her height is 104-135 lbs. She's right in the middle, which is associated with optimal long-term health outcomes.
Scenario 3: Tall Athletic Male
- Height: 6'3" (191 cm)
- Weight: 210 lbs (95 kg)
- BMI: 26.2 (Overweight)
Key Insight: As an athlete with significant muscle mass, BMI may overestimate body fat. While technically "overweight," his body composition could be healthy. This illustrates BMI's limitation for muscular individuals.
Scenario 4: Weight Loss Journey
- Height: 5'6" (168 cm)
- Starting Weight: 200 lbs (91 kg) - BMI 32.3
- Goal Weight: 145 lbs (66 kg) - BMI 23.4
Key Insight: A 55-pound weight loss would move them from obese to normal BMI. At a safe rate of 1-2 lbs per week, this would take 6-12 months. Breaking it into milestones: 185 lbs (BMI 29.9) exits obesity, 155 lbs (BMI 25.0) reaches normal weight.
What Affects Your BMI Results?
Understanding the factors that influence BMI helps you interpret your results more accurately and set realistic health goals.
Muscle Mass
Muscle weighs more than fat by volume. People with high muscle mass (athletes, bodybuilders, manual laborers) may have an "overweight" BMI despite low body fat.
Example: A 5'10" bodybuilder weighing 200 lbs has a BMI of 28.7 (overweight), but their body fat percentage might be only 10%, which is very lean.
Age
As we age, muscle mass typically decreases and body fat increases, even if weight stays the same. Older adults may have higher body fat at the same BMI as younger adults.
Example: A 70-year-old and a 30-year-old, both with BMI 24, likely have different body compositions. The older person may have less muscle and more fat.
Sex Differences
Women naturally have more body fat than men. At the same BMI, women typically have 8-10% more body fat than men due to biological differences.
Example: A man and woman both with BMI 23 are both "normal," but the woman might have 25% body fat (healthy) while the man has 15% body fat (also healthy).
Ethnicity
Different ethnic groups have varying body compositions at the same BMI. Some Asian populations have higher health risks at lower BMIs, while some Pacific Islander populations are healthy at higher BMIs.
Example: WHO suggests lower BMI cutoffs for Asian populations: overweight at BMI ≥23 and obese at BMI ≥27.5, rather than 25 and 30.
Bone Density
People with larger, denser bones weigh more than those with lighter bone structure, which can affect BMI calculations without reflecting body fat differences.
Example: Two people of the same height and body fat percentage could have BMIs differing by 1-2 points due to bone structure differences alone.
Height
BMI may underestimate body fat in very short people and overestimate it in very tall people, as the formula assumes a direct square relationship between height and body volume.
Example: A 6'6" person might have a "normal" BMI but carry excess body fat, while a 5'0" person might have an "overweight" BMI but be quite lean.
Smart BMI Interpretation Strategies
BMI is most useful when you understand how to interpret it in context. Here are evidence-based strategies for making the most of your BMI results:
Monitor your BMI over 3-6 months rather than obsessing over daily fluctuations. Weight varies by 2-5 lbs day-to-day due to water retention, food intake, and digestion. Focus on monthly trends.
Use BMI alongside waist circumference, body fat percentage, and how your clothes fit. A waist over 35" (women) or 40" (men) increases health risks even at normal BMI.
Instead of aiming for "ideal" BMI immediately, set incremental goals. Moving from BMI 35 to 32 (3 points) can significantly improve health markers like blood pressure and blood sugar.
Weigh yourself in the morning before eating, without shoes, on the same scale. Measure height without shoes, standing straight against a wall. Small measurement errors can skew BMI by 1-2 points.
If you're very muscular, have a large frame, or are extremely short/tall, BMI may not accurately reflect your health. Ask your doctor about waist-to-hip ratio or body composition testing instead.
BMI is a screening tool, not a health diagnosis. Pay more attention to blood pressure, cholesterol, blood sugar, energy levels, and fitness than to hitting a specific BMI number.
When BMI Is Most Useful
- Population Health Screening: BMI works well for identifying weight-related health risks in large groups and informing public health policy
- Weight Loss Progress: Tracking BMI changes helps you see if your diet and exercise plan is working over time (aim for 0.5-1 BMI point loss per month)
- Initial Health Assessment: Quick indicator of whether further health testing might be needed, especially when BMI is significantly outside normal range
- Setting Starting Point: Establishes a baseline to compare against as you make lifestyle changes
When to Look Beyond BMI
- If you're very muscular: Athletes, bodybuilders, and people who do heavy physical labor may have "overweight" BMI but healthy body fat levels (10-15% for men, 18-25% for women)
- If you're pregnant: Weight gain during pregnancy is normal and healthy—BMI categories don't apply. Your OB/GYN will monitor appropriate weight gain
- If you're elderly: Some research suggests slightly higher BMI (25-27) may be protective for people over 65, providing reserves during illness
- If you're recovering from illness: After surgery, illness, or eating disorder recovery, BMI may not reflect your health status accurately
- If you have high fitness: Someone who runs marathons or cycles regularly might have healthy cardiovascular markers despite "overweight" BMI
Action Steps Based on Your BMI
BMI Under 18.5 (Underweight):
- Consult a healthcare provider to rule out underlying health conditions
- Focus on nutrient-dense, calorie-rich foods like nuts, avocados, whole grains
- Consider strength training to build muscle mass healthily
BMI 18.5-24.9 (Normal):
- Maintain current weight through balanced diet and regular physical activity
- Aim for 150+ minutes of moderate exercise weekly (brisk walking, cycling, swimming)
- Monitor waist circumference to ensure healthy body fat distribution
BMI 25-29.9 (Overweight):
- Aim for gradual weight loss of 1-2 lbs per week through calorie reduction and increased activity
- Even 5-10% weight loss (10-20 lbs for 200 lb person) improves health markers significantly
- Focus on sustainable diet changes rather than restrictive diets
BMI 30+ (Obese):
- Consult a healthcare provider about weight management strategies and screening for related conditions
- Consider working with a registered dietitian for personalized meal planning
- Start with moderate activity like walking 20-30 minutes daily, gradually increasing intensity
- Explore medical weight loss options if lifestyle changes alone are insufficient
BMI Ranges by Height
This table shows healthy weight ranges for different heights based on a BMI of 18.5-24.9:
| Height | Healthy Weight Range | BMI Range |
|---|---|---|
| 5'0" (152 cm) | 95-128 lbs (43-58 kg) | 18.5-24.9 |
| 5'4" (163 cm) | 108-145 lbs (49-66 kg) | 18.5-24.9 |
| 5'8" (173 cm) | 122-164 lbs (55-74 kg) | 18.5-24.9 |
| 6'0" (183 cm) | 137-184 lbs (62-83 kg) | 18.5-24.9 |
Sources & Methodology
This BMI calculator uses the standard formula established by international health organizations. Our calculations and health category definitions are based on evidence-based guidelines from leading medical authorities.
🏥 BMI Formula & Categories
Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) provide the standard BMI formula and weight category definitions used worldwide.
📊 Health Risk Assessment
National Institutes of Health (NIH) research on BMI and health outcomes informs our health risk category descriptions and recommendations.
🌍 International Standards
WHO Global Database on Body Mass Index provides guidelines for interpreting BMI across different populations and ethnic groups.
📈 Weight Range Calculations
Healthy weight ranges are calculated using BMI 18.5-24.9 thresholds established through epidemiological studies of weight-related health outcomes.
✅ Verification Process
This calculator was reviewed against CDC and WHO BMI guidelines to ensure accuracy of formulas and category definitions. All calculations are performed client-side using JavaScript—no data is sent to servers. Your height and weight information never leaves your device. Last verified: November 2, 2025.
🔗 Learn More From Trusted Sources:
- CDC: About BMI for Adults - Official BMI guidelines and interpretations
- WHO: Obesity and Overweight - Global perspective on BMI and health
- NIH: Calculate Your BMI - BMI and health risk information
- CDC: Adult BMI Calculator - Understanding your BMI results
Common Questions
A healthy BMI range for adults is typically between 18.5 and 24.9. This range is associated with the lowest risk of weight-related health problems. However, BMI is just one indicator of health and doesn't account for muscle mass, bone density, or body composition. A BMI of 22 is often considered ideal for long-term health outcomes.
BMI is calculated by dividing your weight in kilograms by your height in meters squared (kg/m²). For imperial units, the formula is (weight in pounds × 703) ÷ (height in inches)². For example, if you weigh 70 kg and are 1.70 m tall, your BMI would be 70 ÷ (1.70 × 1.70) = 24.2.
BMI is a general screening tool but has limitations. It may not be accurate for athletes with high muscle mass, pregnant women, elderly individuals, or children. BMI also doesn't distinguish between muscle and fat or account for differences in bone density, ethnicity, or body composition. Always consult a healthcare professional for personalized health assessments.
If your BMI is outside the normal range, consult with a healthcare provider who can assess your overall health, body composition, and risk factors. They may recommend additional tests, lifestyle changes, or medical interventions. Remember that BMI is just one metric—factors like diet quality, physical activity, sleep, and stress also significantly impact your health.
BMI for children and teens is calculated the same way as for adults but interpreted differently. Instead of using fixed cutoff points, children's BMI is compared to others of the same age and sex using percentiles. For example, a BMI at the 85th-94th percentile is considered overweight, while 95th percentile and above is obese. Always use pediatric-specific BMI calculators for children under 20.
Disclaimer: This BMI calculator is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. BMI is a screening tool and does not directly measure body fat or health. Always consult with a qualified healthcare provider before making any health-related decisions.