BMI Calculator
Calculate your Body Mass Index (BMI) to assess if you are at a healthy weight.
Your Information
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Fill in your weight and height to see your BMI calculation and personalized results
Calculate Your BMI
Enter your information to see personalized recommendations
Related Health Measurements
BMI is just one indicator. Get a complete picture with these measurements:
Body Fat Percentage
More accurate than BMI for body composition
Basal Metabolic Rate
Calculate daily calorie burn at rest
Ideal Weight Range
Find your target weight based on height
Daily Calorie Needs
Plan nutrition based on activity level
Pro Tip: BMI alone doesn't tell the full story. Combine with body fat and waist measurements for accuracy.
Important: BMI Limitations
BMI may NOT be accurate for:
- •Athletes & Bodybuilders: High muscle mass can show as "overweight" despite low body fat
- •Pregnant Women: Weight gain during pregnancy is normal and necessary
- •Elderly (65+): Muscle loss with age affects accuracy
- •Children & Teens: Growing bodies need age-specific percentile charts
- •Very Muscular People: Muscle weighs more than fat
- •Certain Ethnicities: Asian populations may have health risks at lower BMI thresholds
Why No Gender Option?
BMI calculation is the same for both males and females. The formula doesn't differentiate by gender because it's simply a ratio of weight to height.
However, body composition (muscle vs. fat) differs between genders. Women naturally have higher body fat percentage than men at the same BMI.
💡 For a more accurate assessment, use our Body Fat Calculator which accounts for gender differences.
More Accurate Measurements
Body Fat Percentage
Better indicator of health than BMI. Shows actual fat vs. muscle composition.
→ Use Body Fat CalculatorWaist Circumference
Measures abdominal fat. High waist measurement indicates higher health risk.
• Men: > 40 inches (102 cm) = high risk
• Women: > 35 inches (88 cm) = high risk
Waist-to-Hip Ratio
Compares waist and hip measurements to assess fat distribution pattern.
What is BMI?
Body Mass Index (BMI) is a screening tool that estimates body fat based on height and weight. It was developed in the 1830s by Belgian statistician Adolphe Quetelet.
BMI is widely used because it's simple, quick, and inexpensive. However, it's just one tool and should be combined with other measurements for a complete health picture.
How is it Calculated?
Metric Formula:
Imperial Formula:
The 703 is a conversion factor to make the imperial formula match the metric results.
When to Consult a Doctor
- •BMI under 18.5 or over 30
- •Rapid unexplained weight changes
- •Existing health conditions (diabetes, heart disease)
- •Planning major lifestyle or diet changes
- •Concerns about weight affecting health
BMI Calculator — Common Questions
What is a healthy BMI range?
A healthy BMI is between 18.5 and 24.9 for adults. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is obese. These are general guidelines — a doctor can give a fuller picture based on your individual health.
BMI calculator for women — is it different?
The BMI formula is the same for men and women. However, women naturally carry 6–11% more body fat than men at the same BMI. This means a woman with a BMI of 24 may have a higher body fat percentage than a man with the same BMI. For a gender-accurate measurement, use our Body Fat Calculator.
Does BMI change with age?
The standard BMI formula does not account for age in adults. However, as we age, muscle mass tends to decrease and body fat increases — meaning an older adult can have a "normal" BMI while carrying excess fat. For adults over 65, waist circumference and body fat percentage are considered more reliable indicators.
How to lower your BMI
Since BMI is based on weight and height, lowering it means reducing weight. The most effective approach combines a modest calorie deficit (250–500 calories/day) with regular exercise. Aiming for 0.5–1 kg per week is considered safe and sustainable. Use our Calorie Calculator to find your target.
BMI metric vs imperial — which is more accurate?
Both give the same result — the imperial formula includes a conversion factor (×703) to match the metric output. Our calculator supports both systems so you can use whichever measurements you have. Metric (kg/cm) is slightly easier to use since height in centimetres avoids the feet-and-inches conversion step.
Why BMI isn't the whole story
BMI doesn't distinguish between fat and muscle. A bodybuilder may show as "overweight" despite being very lean. For a complete picture, consider combining BMI with body fat percentage, waist circumference, and metabolic rate. Our Complete Health Assessment covers all six key metrics in one go.