BMI Calculator
Work out your body mass index (BMI) from your height and weight, see where it falls on the WHO adult scale and the weight range that scale calls healthy for your height. BMI can't see muscle, so if you lift, read it next to a body fat estimate. The math runs in your browser: nothing you type is sent anywhere.
Your BMI
Fill in the form and press Calculate to see your BMI, its WHO category and the healthy-weight range for your height.
- Body mass index
- Weight at a BMI of 18.5 for your height
- Weight at a BMI of 24.9 for your height
That's in the WHO's underweight range for adults (below 18.5).
That's in the WHO's healthy-weight range for adults (18.5–24.9).
That's in the WHO's overweight range for adults (25–29.9). If you lift, some of that may be muscle: a body fat estimate tells you more.
That's in the WHO's obesity range for adults (30 or more). BMI can't tell muscle from fat, so a body fat estimate tells you more about your own body.
These are estimates, not medical or dietary advice. How we estimate, with sources
BMI categories for adults
The World Health Organization groups adult BMI into these ranges. The same cut-offs apply to women and men from age 18.
WHO BMI categories for adults (kg/m²)
| Category | BMI |
|---|---|
| Underweight | below 18.5 |
| Healthy weight | 18.5–24.9 |
| Overweight | 25.0–29.9 |
| Obesity, class I | 30.0–34.9 |
| Obesity, class II | 35.0–39.9 |
| Obesity, class III | 40.0 or more |
These categories describe groups of people, not a diagnosis. They are for adults only: children and teens are measured on growth charts for their age and sex, and the categories don't apply during pregnancy.
Why BMI misreads lifters
BMI only knows your height and weight, so it can't tell a kilo of muscle from a kilo of fat. A man who lifts, 180 cm (5 ft 11 in) and 90 kg (198 lb), has a BMI of 27.8, in the overweight range, whether he carries 12% body fat or 30%. The more muscle you carry for your height, the less BMI says about your fat.
BMI vs body fat
Body fat percentage measures what BMI can only guess at: how much of your weight is fat. A tape measure and the U.S. Navy method give you a home estimate in a minute. From there, lean body mass shows the rest of your weight, and FFMI turns it into an index you can compare across heights, like BMI but for lean mass.
Healthy-weight range by height
At each height, these are the weights that give a BMI from 18.5 to 24.9, the WHO's healthy-weight range for adults. Like BMI itself, they don't account for muscle.
Weights with a BMI of 18.5–24.9, by height
| Height | Weight range |
|---|---|
| 150 cm (4 ft 11 in) | 41.6–56.0 kg (92–123 lb) |
| 155 cm (5 ft 1 in) | 44.4–59.8 kg (98–131 lb) |
| 160 cm (5 ft 3 in) | 47.4–63.7 kg (105–140 lb) |
| 165 cm (5 ft 5 in) | 50.4–67.8 kg (112–149 lb) |
| 170 cm (5 ft 7 in) | 53.5–72.0 kg (118–158 lb) |
| 175 cm (5 ft 9 in) | 56.7–76.3 kg (125–168 lb) |
| 180 cm (5 ft 11 in) | 59.9–80.7 kg (133–177 lb) |
| 185 cm (6 ft 1 in) | 63.3–85.2 kg (140–187 lb) |
| 190 cm (6 ft 3 in) | 66.8–89.9 kg (148–198 lb) |
| 195 cm (6 ft 5 in) | 70.3–94.7 kg (155–208 lb) |
Weights are rounded to 0.1 kg, and to whole pounds that stay inside the range. Enter your own height above for your exact range.
When BMI is a useful number
BMI is quick, free and the same everywhere, which is why doctors and studies use it to screen large groups. For one person it's a starting point, not a verdict. If your BMI and your body fat estimate disagree, or you have questions about your health, talk to a doctor.
Watch the trend, not one number
One BMI is a snapshot. The BodyMacros app keeps your weight trend and your lifts in one place and re-estimates your calorie and macro targets each week, so you can see whether you're losing fat and keeping your muscle.
FAQ
What is a healthy BMI?
For adults, the World Health Organization calls a BMI of 18.5 to 24.9 a healthy weight. Below 18.5 is underweight, 25 to 29.9 is overweight and 30 or more is obesity. The cut-offs are the same for women and men, but they describe groups of people, so read your own number next to a body fat estimate.
Is BMI accurate for muscular people?
Not very. BMI divides your weight by your height squared, so muscle counts the same as fat, and a lifter with little body fat can still land in the overweight range. If that's you, a body fat estimate from a tape measure, or your lean body mass and FFMI, says more about your body than BMI can.
Which is better, BMI or body fat percentage?
They answer different questions. BMI needs only height and weight, so it's quick to compare across people. Body fat percentage estimates how much of your weight is fat, which is what most people want to know when they diet or train. If you lift, body fat percentage tells you more about your own body.
How is BMI calculated?
Divide your weight in kilograms by your height in metres, squared. At 1.80 m and 80 kg, that's 80 ÷ (1.8 × 1.8) = 24.7. In pounds and inches, multiply your weight by 703 and divide by your height in inches, squared. The calculator above does either for you and shows the WHO category.
Track this in the app
Log your food and your lifts in one place. Your estimates adjust each week to how you eat and train.
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