BMI calculator
BMI (body mass index) is a simple marker relating your weight to your height. Useful for placing a population, it has real limits for a strength trainee. This tool gives you your BMI and your 'healthy' weight range, while explaining how to read it honestly.
Enter your height and weight.
How to read your BMI
BMI is calculated by dividing weight (kg) by height squared (m). Reference thresholds: below 18.5 = underweight, 18.5 to 25 = normal, 25 to 30 = overweight, above 30 = obesity. The 'healthy' weight range shown corresponds to a BMI between 18.5 and 25 for your height.
These thresholds are statistical markers set on large populations. They give an initial orientation but do not replace medical advice or a body-composition measurement.
Why BMI misleads athletes
BMI does not distinguish muscle from fat. Yet muscle is denser than fat: a muscular person weighs more at equal volume, and can therefore show an 'overweight' BMI while being lean and perfectly healthy.
For a strength trainee, markers like waist circumference, progress photos or a body-fat estimate are far more telling than BMI alone. Use BMI as a rough marker, nothing more.
Beyond BMI: better ways to gauge your shape
Since BMI ignores body composition, complement it with finer markers: waist circumference (a good indicator of belly fat), the trend of your photos and measurements, or a body-fat estimate. Together they tell your condition far better than a single number.
For a trainee, the scale alone is misleading: building muscle can raise your weight — and BMI — while your figure gets leaner. Track several signals at once rather than just one.
Frequently asked questions
Is a high BMI necessarily bad?expand_more
Not necessarily. In a muscular person, a BMI above 25 can reflect muscle mass, not excess fat. That is precisely the index's big limitation. Always cross-check it with other markers before concluding.
Does BMI work for everyone?expand_more
It is less relevant for very muscular athletes, older adults, pregnant women and children (who have their own charts). For general adult use, it remains a handy first marker, to be interpreted with common sense.
What BMI counts as normal?expand_more
A BMI between 18.5 and 25 is considered normal for an adult. Below that is underweight; above it, overweight then obesity. These thresholds are population markers, not an individual diagnosis.
Does BMI depend on sex?expand_more
The calculation is identical for women and men, and the standard thresholds are the same. However, at equal BMI, body composition often differs — which is why cross-checking with other measures helps.
How do I calculate my BMI?expand_more
Divide your weight in kilos by the square of your height in metres. For example, 75 kg at 1.80 m gives 75 ÷ (1.80 × 1.80) ≈ 23.1. The tool above does the calculation and places the result on the scale.
Track your progress, not just your calculations
Log your workouts, loads and weight, and watch your curve climb — for free.