Health & fitness calculators
Free, instant calculators for body composition, daily nutrition, hydration, and wellness. Understand your body better — no signup, no ads, no data collection.
About health & fitness calculators
These tools use the same formulas trusted by doctors, dietitians, and fitness professionals worldwide. They turn complex equations into instant, personalised answers — so you can make informed decisions about your body and nutrition without searching through medical textbooks.
Which calculator should I use?
- Want to know if your weight is healthy? Start with the BMI calculator, then check body fat for a more complete picture, and ideal weight for a target range.
- Trying to lose or gain weight? Use the calorie calculator to find your TDEE, then the macros calculator to split calories into protein, carbs, and fat.
- Curious about your metabolism? The BMR calculator shows how many calories you burn at rest — useful for understanding your baseline energy needs.
- Expecting a baby? The due date calculator estimates your delivery date and shows a trimester timeline with key milestones.
Are these medically accurate?
Every calculator uses peer-reviewed, clinically validated formulas — the Mifflin-St Jeor equation for BMR, the U.S. Navy method for body fat, and Naegele's Rule for due dates. They are screening tools, not diagnoses. For medical decisions, use these results as a starting point and consult a healthcare professional.
Common questions
Are these health calculators free?
Yes. Every calculator is completely free, with no signup, no email capture, and no paywall. All calculations run in your browser — your data never leaves your device.
Which is more accurate — BMI or body fat percentage?
Body fat percentage is a more direct measure of body composition. BMI is a quick screening tool based on height and weight, but it can misclassify muscular people as overweight. For the best picture, use both together.
How many calories should I eat to lose weight?
Eat about 500 calories below your TDEE (Total Daily Energy Expenditure) for a safe weight loss of ~0.5 kg (1 lb) per week. Use the calorie calculator to find your TDEE, then the macros calculator to plan your diet.
Do these calculators account for age and sex differences?
Yes. The calorie, BMR, body fat, and ideal weight calculators all adjust for sex, and the calorie and BMR calculators account for age. These factors significantly affect metabolism and body composition.
Can I use these during pregnancy?
The due date calculator is designed for pregnancy. For BMI and calorie calculations during pregnancy, standard formulas may not apply — consult your doctor for personalised guidance on nutrition and weight gain during pregnancy.