BMI Calculator
BMI (Body Mass Index) is your weight in kilograms divided by your height in metres squared. A result between 18.5 and 24.9 is the healthy range for most adults. Enter your height and weight below to get your BMI, your category, and the healthy weight range for your height.
Free, instant, and works in metric or imperial. BMI is a quick screening number — pair it with the body-fat calculator if you train with weights, since BMI can't tell muscle from fat.
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Healthy range |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obese |
BMI is a population screening number, not a diagnosis — it can't tell muscle from fat. If you lift regularly, pair it with the body-fat calculator for a fuller picture.
What BMI can and can't tell you
BMI was designed to screen large populations, and at that job it works: across millions of people, higher BMI correlates with higher health risk. For one individual it's blunter — it doesn't know whether your kilograms are muscle or fat, where you carry weight, or how fit you are.
Use it as a starting reference point, not a verdict. If your BMI sits outside the healthy band, the fix is rarely dramatic: consistent strength training, daily movement and a modest calorie adjustment move both BMI and the numbers that matter more — strength, waist measurement and body-fat percentage. The TDEE calculator gives you the calorie targets; a free weekly routine covers the training.
Turn the number into a plan
SSS Workout Assistant builds a free weekly training routine and calorie targets from your profile, then tracks every workout so the trend moves the right way.
Start freeFrequently asked questions
What is a healthy BMI?
A BMI between 18.5 and 24.9 is classed as the healthy range for most adults. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is classed as obese. These are population screening bands, not individual diagnoses.
Is BMI accurate if I lift weights?
BMI can't tell muscle from fat, so muscular people often score 'overweight' while carrying little body fat. If you train regularly, treat BMI as a rough screen and use a body-fat estimate (like the tape-measure calculator on this site) or waist measurement alongside it.
How is BMI calculated?
BMI is your weight in kilograms divided by your height in metres squared (kg/m²). In imperial units the same formula is weight in pounds divided by height in inches squared, multiplied by 703. This calculator handles both unit systems automatically.
How can I move my BMI toward the healthy range?
Sustainably: a modest calorie deficit (if above the range) or surplus (if below), two to four strength sessions a week to keep or build muscle, and daily walking. Aim for roughly 0.25–0.75 kg of change per week — the strength training is what keeps weight change coming from fat, not muscle.
Should children or athletes use this BMI calculator?
This calculator uses adult cut-offs, so it isn't suitable for children or teens, whose BMI is assessed with age-specific charts. Competitive athletes with high muscle mass should rely on body-composition measures instead — BMI routinely misclassifies them.
This calculator is a general fitness tool, not medical advice. Talk to a healthcare professional about what your BMI means for you personally.