8 calculators
Health & Fitness Calculators
Most health numbers are simple arithmetic wrapped in unfamiliar formulas — and the formula you pick genuinely changes the answer.
All Health & Fitness calculators
About these calculators
These eight tools cover body composition and daily energy. Where several accepted formulas exist, the calculator shows you which one it used and, in the case of ideal weight, gives you all four side by side rather than picking one and hiding the rest. The children's BMI tool is kept separate from the adult one on purpose: child BMI is read as an age-and-sex percentile, not against fixed adult thresholds, and treating them the same gives misleading results.
These are general-population estimates. They do not account for muscle mass, pregnancy, medical conditions or athletic build, and they are not a substitute for advice from a doctor.
Which health calculator do you need?
| Your question | Use this |
|---|---|
| Is my weight healthy for my height? | BMI calculator |
| Is my child a healthy weight for their age? | BMI calculator for children |
| How many calories should I eat to lose weight? | Calorie calculator |
| How many calories does my body burn at rest? | BMR calculator |
| How many grams of carbs, protein and fat should I eat? | Carbohydrate and macro calculator |
| What is my body fat percentage? | Body fat calculator |
| What should I weigh for my height? | Ideal weight calculator |
| What time should I go to bed? | Sleep calculator |
How these numbers fit together
Most of these tools build on each other. Your BMR is what your body burns at rest. Multiply it by an activity factor and you get your TDEE — your daily calorie needs. Eat about 500 calories below that and most people lose roughly 0.5 kg (1 lb) a week. Split those calories into macros, and track progress with body fat as well as BMI, since BMI cannot tell muscle from fat.
Every result here is an estimate for healthy adults. These tools do not replace advice from a doctor or dietitian, especially during pregnancy, for children, or if you have a medical condition.