BMI Calculator for Women
Calculate your Body Mass Index with the WHO category, your healthy weight range, and a women-specific estimated body fat % — plus age-aware context. Free, private, 100% in your browser.
Your results
WHO category: under 18.5 underweight · 18.5–24.9 normal · 25–29.9 overweight · 30+ obese
Age context: the WHO categories do not change with age, but body composition does. At the same BMI, a 55-year-old woman typically carries more fat and less muscle than a 25-year-old, with fat shifting toward the abdomen around menopause. That is why the body-fat estimate above rises with age even when BMI is identical — treat it as context, not a different category.
How it works
BMI = weight (kg) ÷ height (m)². Example: a woman who weighs 65 kg and is 165 cm tall: 65 ÷ (1.65 × 1.65) = 23.88 — the WHO normal range (18.5–24.9).
Healthy weight range = 18.5 × h² to 24.9 × h². For 165 cm that is 50.4–67.8 kg.
Body fat estimate (Deurenberg, women) = 1.20 × BMI + 0.23 × age − 5.4. For the example above at age 30: about 30.2%. This is a population-level estimate, not a measurement.
Scope boundary
This tool is women-specific: it adds a body-fat % estimate calibrated for women (Deurenberg formula), age-aware body-composition notes, and women-focused guidance. For the plain, general-purpose BMI calculation (unisex, no body-fat estimate), use our BMI Calculator.
Frequently asked questions
Is BMI calculated differently for women?
No — the BMI formula itself is identical for women and men: weight in kilograms divided by height in meters squared. What differs is the interpretation. This calculator adds women-specific context: an estimated body fat percentage from the Deurenberg formula calibrated for women, plus age-aware notes, because body-fat distribution and muscle mass change differently with age in women.
What is a healthy BMI for a woman?
The WHO defines the same healthy BMI range for all adults: 18.5 to 24.9. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is obese. These are screening bands for populations, not a personal diagnosis — muscle mass, pregnancy, and menopause can all shift what a given BMI means for an individual woman.
Does a healthy BMI change with age?
The WHO BMI categories themselves do not change with age — 18.5 to 24.9 remains the reference band for adults. What changes is body composition: with age, women typically carry more fat and less muscle at the same BMI, and fat tends to shift toward the abdomen. That is why this tool shows an age-adjusted body-fat estimate next to your BMI, as context rather than a different category.
How accurate is the body fat percentage estimate?
The Deurenberg estimate is a population-level approximation with a typical error of around 3 to 4 percentage points compared with lab methods such as DEXA. It is useful for tracking trends and getting a rough picture, but it is not a measurement of your body. For a precise value, a DEXA scan, hydrostatic weighing, or a trained skinfold assessment is needed.
What is the Deurenberg formula?
For adult women, the Deurenberg formula estimates body fat percentage as: BF% = 1.20 x BMI + 0.23 x age - 5.4. It was derived by Deurenberg et al. from densitometry data and is the version this calculator uses. It applies to adults and becomes less reliable at very high or very low body fat levels.
Can I use this BMI calculator during pregnancy?
No. BMI is not a valid measure during pregnancy because weight gain includes the baby, placenta, and extra fluid. Pregnant women should follow their healthcare provider's guidance on healthy weight gain instead of using a BMI calculator.
How do I calculate my BMI manually?
Divide your weight in kilograms by your height in meters squared. Example: a woman who weighs 65 kg and is 1.65 m tall has a BMI of 65 / (1.65 x 1.65) = 23.88, which falls in the WHO healthy range of 18.5 to 24.9.
How is this different from the general BMI calculator?
The general BMI calculator covers the core unisex calculation: BMI value, WHO category, and healthy weight range. This women-specific version adds three things on top: a body fat percentage estimate using the Deurenberg formula calibrated for women, age-aware body-composition context, and women-focused guidance. Use the general calculator if you only need the plain BMI number.
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