BMI — weight divided by height squared — is the standard quick screen for weight categories: under 18.5 is underweight, 18.5–24.9 is the healthy range, 25–29.9 is overweight, and 30+ is obese. It is a screening tool, not a diagnosis: it cannot tell muscle from fat, so athletes should read it with that grain of salt.
Knowing your number is only half the question — the other half is what to eat. Add your age, sex, and activity level and the calculator estimates your TDEE (total daily energy expenditure) with the Mifflin-St Jeor equation, the formula dietitians actually use. All computed locally; nothing leaves your device.
Check your numbers in 3 steps
- Open the faymox BMI Calculator.
- Enter your height and weight — cm/kg or ft–in/lb, whichever you know.
- See your BMI and category right away — then add age, sex, and activity level for your daily calorie needs (TDEE).
FAQ
What is a healthy BMI range?
18.5 to 24.9 is the standard healthy range for adults. Below 18.5 is underweight, 25–29.9 overweight, 30 and above obese.
Is BMI accurate for athletes?
Not always — muscle is dense, so very muscular people can score “overweight” while being perfectly healthy. BMI is a population screening tool, not a personal verdict.
What is TDEE?
Total Daily Energy Expenditure — roughly how many calories your body burns per day. Eat near it to maintain weight, below it to lose, above it to gain.