Free tool
BMI calculator
Your body mass index, its category and the healthy weight range for your height
How the calculator works
Body mass index is your weight in kilos divided by your height in metres, squared 1. Someone who weighs 70 kg and is 1.70 m tall has a BMI of 70 ÷ (1.70 × 1.70), about 24.2. The calculator also works out the healthy weight range for your height: a BMI from 18.5 to 24.9. It's for adults only, and nothing you enter leaves your browser.
| Height | Healthy weight |
|---|---|
| 150 cm (4 ft 11 in) | 41.6 to 56.0 kg (92 to 124 lb) |
| 160 cm (5 ft 3 in) | 47.4 to 63.7 kg (104 to 141 lb) |
| 170 cm (5 ft 7 in) | 53.5 to 72.0 kg (118 to 159 lb) |
| 180 cm (5 ft 11 in) | 59.9 to 80.7 kg (132 to 178 lb) |
| 190 cm (6 ft 3 in) | 66.8 to 89.9 kg (147 to 198 lb) |
What BMI can't tell you
BMI is a quick screening measure, one health indicator among many. It doesn't measure body fat directly and can't tell fat from muscle or bone 3, so a muscular person can read as overweight. Waist measurements can also help show whether weight is putting your health at risk 1.
- Children and teenagers: BMI is compared with growth charts for their age and sex, not with the adult categories 1.
- Pregnancy: weight gain is expected and healthy, so the adult categories don't apply.
- Some Asian populations: a WHO expert group found a substantial share of Asian people at high risk of type 2 diabetes and heart disease below a BMI of 25. It kept the international categories but suggested countries could also act at 23 and 27.5 4.
BMI in Fasting Tracker
Add your height in Fasting Tracker and it shows your BMI and its category next to your weight, from your weigh-ins or Apple Health. When you set a weight goal, the app won't let you aim below a healthy BMI for your height. To see when you could get there, try the weight goal calculator.
Sources
- World Health Organization. Obesity and overweight. Fact sheet. www.who.int/news-room/fact-sheets/detail/obesity-and-overweight
- World Health Organization. Body mass index (BMI). Global Health Observatory. www.who.int/data/gho/data/themes/topics/topic-details/GHO/body-mass-index
- Centers for Disease Control and Prevention. About Body Mass Index (BMI). 2025. www.cdc.gov/bmi/about/index.html
- WHO Expert Consultation. Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet. 2004;363(9403):157-63. doi.org/10.1016/S0140-6736(03)15268-3
Keep reading
- When will I reach my goal weight?Enter your weight and your goal to see when you could get there at a steady, sustainable pace
- How much weight can you lose with intermittent fasting?Honest numbers from the trials, what to expect in weeks and months, and why it slows down
Plateaus: what to do when progress stallsWhy weight loss slows down, how to tell a real plateau from normal ups and downs, and what actually helps
A note on health
Fasting Tracker is designed for general wellness and is not a medical device. Fasting is not right for everyone. If you are pregnant, diabetic, have a history of eating disorders or take medication, talk to your doctor first, and before any extended fast.