Home / BMI Calculator
BMI Calculator
Work out your body mass index (BMI) from your height and weight, and see which standard category it falls in. Free, with no sign-up.
Example filled in: 70 kg at 175 cm tall gives a BMI of 22.86 — healthy weight.
Your BMI
Results appear here.
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Healthy weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obesity |
How to use the BMI calculator
- Pick metric (kg and cm) or US units (pounds and feet/inches).
- Type your weight and your height.
- Press Calculate my BMI. The panel on the right shows your BMI, your category, and the healthy weight range for your height.
Worked example — 70 kg at 175 cm
BMI is your weight in kilograms divided by your height in meters, squared. At 175 cm tall, height in meters is 1.75, and 1.75 squared is 3.0625. Divide 70 by 3.0625 and you get 22.86 — healthy weight. For the same height, the healthy range runs from 56.66 kg (BMI 18.5) to 76.26 kg (BMI 24.9). Put the same numbers into the calculator above and you will get the same answer. For comparison, 90 kg at the same height gives a BMI of 29.39 — overweight.
Not medical advice. BMI is a rough screening number. It does not measure body fat, muscle, or health on its own — a very muscular person can have a high BMI and be fit, and a normal BMI does not rule out health problems. Use it as a starting point, and talk to a doctor or other health professional about what it means for you.
Frequently asked questions
What is a healthy BMI?
A BMI from 18.5 to 24.9 is classed as healthy weight. Below 18.5 is underweight, 25.0 to 29.9 is overweight, and 30.0 and above is obesity.
How is BMI worked out?
Divide your weight in kilograms by your height in meters, squared. In US units, multiply your weight in pounds by 703, then divide by your height in inches, squared.
Is BMI accurate?
It is a rough guide, not a diagnosis. It does not tell muscle from fat, and it does not suit everyone — athletes, older adults, and pregnant people, for example. Doctors use it alongside other checks.
What is my healthy weight range?
Type your height into the calculator above and it shows the weight range for a BMI of 18.5 to 24.9 at your height. At 175 cm, that range is 56.66 kg to 76.26 kg.
Is my height and weight stored anywhere?
No. The calculation runs in your browser and your numbers are never sent to any server or stored.
Sources and method. WHO/CDC BMI categories: underweight below 18.5, healthy 18.5–24.9, overweight 25.0–29.9, obesity 30.0 and above. Worked examples checked in Node: 70 kg at 175 cm = BMI 22.86 (healthy); 90 kg at 175 cm = BMI 29.39 (overweight); healthy range 56.66–76.26 kg.