This BMI calculator is built specifically for women, using height, weight, age, and optional waist measurement to calculate Body Mass Index alongside an estimated daily calorie need based on your activity level. It supports both metric (kg/cm) and imperial (lb/ft-in) units.
How to use this BMI calculator
- Choose Metric or Imperial units.
- Enter your height and weight in the selected units.
- Enter your age and, optionally, your waist measurement.
- Select your activity level, then click Calculate BMI.
The BMI formula
BMI = Weight (kg) ÷ Height (m)²
For imperial units, the equivalent formula is weight in pounds divided by height in inches squared, multiplied by 703. The result is the same BMI number regardless of which unit system you use — only the formula’s constants change to match.
Why activity level and waist measurement are included
BMI alone only accounts for height and weight, so this calculator adds your activity level to estimate a daily calorie need using it as a multiplier on your base metabolic rate — useful context alongside the BMI figure itself. Waist measurement is optional but gives an additional data point, since BMI doesn’t distinguish between muscle and fat or account for where weight is carried on the body.
Frequently asked questions
Is BMI calculated differently for women than for men?
No — the BMI formula itself is identical for everyone. What can differ is interpretation: healthy body fat percentage ranges and typical body composition vary somewhat by sex, which is why this calculator adds context like waist measurement rather than changing the core BMI formula.
Why does the calculator ask for my activity level if it’s just measuring BMI?
The activity level isn’t used in the BMI formula itself — it feeds a separate daily calorie estimate shown alongside your BMI result, giving you two related but distinct pieces of information in one place.
Does a high BMI always mean high body fat?
Not necessarily. BMI doesn’t distinguish between muscle and fat mass, so very muscular individuals can show a higher BMI without correspondingly high body fat. It’s a useful screening tool but not a complete measure of body composition on its own.