Fitshare
Free, no sign-upBMI calculatorWhat's a healthy weight for me?
Enter your height and weight to get your BMI (body mass index), which range it falls in, and the healthy weight range for your height. It runs in your browser, and nothing is sent anywhere.
Enter your height and weight and press Calculate. Your BMI and healthy weight range show up here.
Your result
Your BMI
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Healthy weight for your height
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BMI can't tell muscle from fat, so for people who lift it can read “overweight” without any excess fat. It's a screening number, not a diagnosis — for questions about your weight, talk to your doctor.
How BMI is calculated
BMI (body mass index) is your weight in kilograms divided by your height in metres squared. The formula is the same for men and women:
BMI = weight (kg) ÷ height (m)²
For example: 70 ÷ (1.75 × 1.75) = 70 ÷ 3.06 = 22.9
The World Health Organization groups adult results into four ranges:
| BMI | Range |
|---|---|
| < 18.5 | Underweight |
| 18.5 – 24.9 | Healthy weight |
| 25 – 29.9 | Overweight |
| 30+ | Obesity |
The healthy weight range for a height is the same formula turned around: 18.5 × height² to 24.9 × height². At 170 cm, for example, that's 53.5 to 72 kg.
What BMI can't see. It doesn't know how much of your weight is muscle, where your fat sits, or your age or ethnicity. Someone who lifts can have a BMI of 27 at low body fat, and someone with a “healthy” BMI can carry belly fat. Waist size and body-fat percentage fill in the picture, and for questions about your weight — your doctor.
From the number to a plan
BMI tells you where you stand, not what to do. If you want to lose weight, the next step is knowing how much your body burns in a day — the TDEE calculator — and how much to eat to lose at a safe pace, in the calorie deficit calculator.
In Fitshare you weigh in and log it, and the app shows your weight trend over time, next to your workout log and nutrition tracking. You log a meal in a sentence or a photo, and a workout in a sentence. More about the nutrition tracker.
Questions about BMI
How do you calculate BMI?
Divide your weight in kilograms by your height in metres squared: BMI = kg ÷ m². For example, 70 kg and 1.75 m: 70 ÷ (1.75 × 1.75) = 22.9. The formula is the same for men and women.
What is a healthy BMI?
For adults, a BMI from 18.5 to 24.9 counts as healthy by the World Health Organization. Under 18.5 is underweight, 25 to 29.9 overweight, and 30 or more obesity. The ranges are the same for men and women.
What's a healthy weight for my height?
Multiply your height in metres squared by 18.5 and by 24.9. At 160 cm that's 47.4 to 63.7 kg, at 170 cm 53.5 to 72 kg, and at 180 cm 59.9 to 80.7 kg. The calculator above works out the range for your height.
Does BMI work if I lift weights?
Less so. BMI counts all your weight as one, and muscle is denser than fat, so someone who has built muscle can read “overweight” at low body fat. For people who train, waist size, body-fat percentage and the weight trend over time tell you more.
What about BMI for children and teens?
Under 18 the adult ranges don't apply. A child's or teen's BMI is compared with growth charts for their age and sex (percentiles), and that's best done with their paediatrician.
Is the calculator free? Do I need to sign up?
Free, with no sign-up. The calculation runs in your browser, and the height and weight you enter aren't sent to us or stored. If you want to track your weight over time, open an account in the app, which is free too.
More calculators
See the trend, not just the number
Download Fitshare, log your weight, workouts and meals, and watch how it all moves over the weeks.