FitForge

BMI Calculator

Body mass index is a quick screen that compares weight with height. Here is yours, what the categories mean, and where BMI goes wrong for people who train.

Units
Sex
lb
Height
ft
in

Your BMI

25.2

Overweight

Healthy range for your height

129–174lb

BMI 18.5–24.9

Same BMI, very different bodies

BMI divides weight by height squared and stops there. It cannot see what the weight is made of. Switch between two people with identical height and weight.

A 1.80 m, 97 kg lifter at 12% body fat. BMI 29.9: "overweight", one step from "obese". Waist 81 cm.

For a quick risk read beyond BMI, the NHS and WHO also use waist size: keep it under half your height. If you lift, pair BMI with the body fat calculator or FFMI.

BMI categories (WHO, adults)

BMICategory
Below 18.5Underweight
18.5–24.9Healthy weight
25–29.9Overweight
30–34.9Obesity class I
35–39.9Obesity class II
40 and aboveObesity class III

BMI was devised by Adolphe Quetelet in the 1830s to describe populations, and it still works well for that. For individuals it is a starting point. It is not designed for children and teens, who need age-specific percentiles.

Questions lifters ask

What is a healthy BMI?

The World Health Organization classifies 18.5–24.9 as a healthy weight for adults, 25–29.9 as overweight and 30 or above as obesity. Some Asian health bodies use lower cut-offs (23 and 27.5).

Is BMI accurate for athletes and lifters?

Often not. BMI only uses height and weight, so a muscular person can be labelled overweight or obese at a low body fat. Body fat percentage or FFMI tell you more if you lift.

How is BMI calculated?

Weight in kilograms divided by height in metres squared. In pounds and inches: 703 × weight ÷ height².

What is the healthy weight range for my height?

The calculator shows the weight range that gives a BMI of 18.5–24.9 at your height. It is a population guide, not a personal target.

Keep calculating