Body Mass Index (BMI) is a quick weight-for-height check. Our main calculator shows BMI alongside your TDEE and calorie targets.
BMI does not tell you how many calories to eat. Use BMR and TDEE for daily targets, then a calorie deficit if you want to lose fat.
BMI ignores muscle mass, bone density, and where fat is stored. It is useful as a starting screen — not the full picture. Read: how our formulas work.
BMI compares your weight with your height. You can calculate it in metric or imperial units, and both give the same result:
The calculator shows BMI with one decimal place, next to your daily calorie targets. A BMI of 24.2 is in the WHO normal range, but it is above the first action point for many Asian populations, as the next section explains.
The World Health Organization (WHO) uses the same BMI categories for adults around the world. In 2004, a WHO expert group found that many Asian populations have a higher risk of type 2 diabetes and heart disease at BMI values below 25. The group kept the international categories but suggested extra public health action points: 23 for increased risk and 27.5 for high risk.
| BMI | WHO international category | Risk level for many Asian populations (WHO, 2004) |
|---|---|---|
| Below 18.5 | Underweight | Underweight |
| 18.5–22.9 | Normal | Lower risk |
| 23.0–24.9 | Normal | Increased risk |
| 25.0–27.4 | Overweight | Increased risk |
| 27.5–29.9 | Overweight | High risk |
| 30.0 and above | Obese | High risk |
In India, a 2025 expert guideline defines obesity in adults as a BMI above 23, and uses waist size (90 cm or more for men, 80 cm or more for women) and health checks to judge how serious it is. The Calorie Cal calculator shows the international WHO category, so users in India and other Asian countries should also compare their result with these lower cut-offs.
BMI is a quick screening number. It does not diagnose any health problem. Keep these limits in mind:
If your BMI is outside the healthy range for your background, or you are worried about your weight, talk to a doctor.
Waist-to-height ratio divides your waist size by your height, in the same unit. A review of many studies found that it was a better screening tool for heart and metabolic risk than BMI or waist size alone. A simple rule is to keep your waist less than half your height, which means a ratio below 0.5.
The calculator does not measure waist-to-height ratio. Use a tape and the division above, and use the result together with your BMI.
BMI = weight (kg) ÷ height (m)². For imperial: multiply weight in pounds by 703, then divide by height in inches squared.
For most adults, WHO ranges are: under 18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, 30+ obese. BMI is a screening tool, not a diagnosis.
BMI can overestimate body fat in muscular people and underestimate it in older adults who lost muscle. Pair BMI with waist measurement and body composition when possible.
Research shows that many Asian populations have more body fat and a higher risk of type 2 diabetes and heart disease at the same BMI as European populations. For this reason, WHO experts suggested action points of 23 and 27.5 for Asian populations.
Not with the adult categories. For people under 18, doctors compare BMI with growth charts for the same age and sex.
Yes. This can happen when muscle mass is low, for example in people who do not exercise. A large waist with a normal BMI is a good reason to check your waist-to-height ratio.
It depends on your height. At 1.70 m, one BMI point equals about 2.9 kg, because 1.70 × 1.70 = 2.89. To plan a safe rate of loss, see the calorie deficit calculator.
No. Being underweight also carries health risks. Aim for the healthy range for your background, and look at your waist size, habits and how you feel.
Studies and guidelines this page is based on: