Free Online Health Calculators: BMI, BMR/TDEE, Body Fat, WHR, Calorie Targets & Macros
Free, private online calculators for BMI, BMR/TDEE, body fat, waist-to-hip ratio, calorie targets, macronutrients and water intake — all in your browser, metric & imperial.
Authoritative, verifiable formulas
BMI uses WHO standards; BMR uses Mifflin–St Jeor; body fat uses the U.S. Navy circumference method.
Metric / imperial toggle
Switch freely between cm/kg and ft-in/lb — convenient for both international and US users.
Local-first, zero upload
Height, weight, age and measurements are calculated entirely on your device; nothing is sent to a server.
FinCompute Health combines the most-used tools for weight management and meal planning into one privacy-first workspace: body composition metrics (BMI, BMR/TDEE, body fat & lean mass, waist-to-hip ratio) and nutrition planning (calorie target, macronutrients, water intake). Every calculation runs locally in your browser — no sign-up, no tracking — with metric/imperial support and full localization into six languages.
From BMI to body fat: why you need more than one metric
BMI uses only height and weight and cannot tell muscle from fat; body fat percentage and waist-to-hip ratio reveal composition and fat distribution. Keeping these tools together lets you cross-check — a muscular person with a high BMI but low body fat and normal waist is very different from someone "normal weight" with excess visceral fat.
BMR/TDEE: the scientific foundation of calorie targets
The first step in fat loss or muscle gain is knowing how many calories you burn. We use the Mifflin–St Jeor equation recommended by the Academy of Nutrition and Dietetics for BMR and apply five activity factors to get TDEE, then quantify a realistic daily deficit or surplus instead of arbitrary crash-diet numbers.
Macros and water: turning calories into food
At the same calorie level, different protein/carb/fat ratios change satiety, training performance and body composition. We offer balanced, high-protein, low-carb and ketogenic presets plus custom ratios, alongside a body-weight- and climate-based water recommendation to translate goals into daily grams and milliliters.
Local by design: sensitive body data never leaves your device
Height, weight, age and circumferences are sensitive personal information. This module has no backend, no analytics SDK and no cookie tracking; numbers live only in your browser and can be cleared from the history panel at any time.
FAQ
QAre these health calculators accurate?
All formulas use published authoritative standards (WHO, Mifflin–St Jeor, U.S. Navy, NASEM), but they are population estimates. Individual results vary with body composition, hormones and health conditions, so they are for reference only and not medical advice.
QIs my height and weight uploaded?
No. Every calculation runs locally in your browser; there is no data endpoint or third-party analytics script, and the tools work offline.
QHow many calories should I eat per day to lose weight?
A daily deficit of 300–500 kcal below TDEE is realistic (roughly 0.3–0.5 kg/week). Intake should not fall below BMR; women are generally advised not to go below 1200 kcal/day or men below 1500 kcal/day.
QWhat is a healthy body fat percentage?
ACE reference ranges: men — fitness 14–17%, acceptable 18–24%; women — fitness 21–24%, acceptable 25–31%. Women need higher essential fat for reproductive health.
QDoes a normal BMI mean I am healthy?
Not necessarily. BMI does not capture fat distribution; people with "normal weight obesity" may have normal BMI but elevated body fat or waist size and still face metabolic risk. Combine BMI with waist circumference, WHR and body fat.
QHow much water should I drink per day?
A common estimate is 35 ml/kg body weight, adjusted up for activity and heat — about 2.3 L for a 65 kg adult. About 20% of total water comes from food; pale, clear urine is a simple sign of adequate hydration.