Enter your stats and activity level to get your BMR, maintenance calories, and targets for weight loss or gain.
BMR is calculated with the Mifflin-St Jeor equation — 10×weight(kg) + 6.25×height(cm) − 5×age + 5 for men, and the same minus 161 instead of plus 5 for women. Published in 1990 and re-validated repeatedly since, it's generally considered more accurate for the modern population than the older 1919 Harris-Benedict formula, which tends to overestimate BMR by 5–15% for most people today. TDEE (Total Daily Energy Expenditure) multiplies BMR by an activity factor to estimate total calories burned per day, including exercise and general movement.
Harris-Benedict (revised 1984 version: 88.36 + 13.4×kg + 4.8×cm − 5.7×age for men) is still widely quoted and used in some clinical settings, but independent validation studies consistently find Mifflin-St Jeor closer to measured resting metabolic rate for the general population, which is why this calculator defaults to it. The two formulas typically land within 3–5% of each other for an average-build adult — the gap widens for people at the extremes of body composition, which is exactly the case Katch-McArdle below is built for.
Katch-McArdle calculates BMR from lean body mass instead of total weight: 370 + 21.6 × lean mass (kg). Because fat tissue burns far fewer calories at rest than muscle, this formula is more accurate for people who are notably lean or muscular — bodybuilders, athletes — where Mifflin-St Jeor's weight-only approach can misjudge BMR. Its accuracy depends entirely on an accurate body-fat percentage input, which most people don't have precisely measured (a DEXA scan or hydrostatic weighing gives the most reliable figure; bioelectrical scales are a rough estimate at best) — that's why this calculator uses Mifflin-St Jeor as the general-purpose default.
Weight loss target subtracts 500 calories from TDEE, and weight gain target adds 500 — a 500-calorie daily deficit or surplus roughly corresponds to about 0.45 kg (1 lb) of change per week, since one pound of body fat represents approximately 3,500 kcal. This is a moderate, sustainable pace recommended by most dietitians; a more aggressive 750–1,000 calorie deficit accelerates loss but is harder to sustain and risks more muscle loss alongside fat.
Protein and carbohydrates provide 4 kcal per gram, fat provides 9 kcal per gram — the macro breakdown above splits your maintenance calories into grams of each using whichever style you pick. "Balanced" (30/40/30) suits general health goals; "Higher protein" (40/30/30) supports muscle retention during a calorie deficit or muscle gain during a surplus, since protein needs don't scale down just because calories do; "Lower carb" (35/20/45) suits people managing blood sugar or following a lower-carbohydrate eating pattern. None of these is more "correct" than another — the right split depends on your goal, medical situation, and what you can sustain.
These are population-average formulas — actual metabolism varies with muscle mass, genetics, thyroid function, and other health conditions, and studies show even the best equations can be off by 10% or more for a given individual. Treat the numbers as a well-informed starting point, not a precise measurement, and adjust based on how your actual weight responds over 2–3 weeks of consistent tracking — that real-world feedback beats any formula.
TDEE is a maintenance estimate, not a daily prescription — actual intake naturally varies day to day with social meals, travel, and appetite, and what matters for weight management is the average over a week or two, not hitting an exact number every single day. Weekly averaging also smooths out water-weight fluctuations that make day-to-day scale readings noisy.
The physiology and formulas are universal — a calorie is a calorie regardless of country. What differs is units and labeling conventions: US nutrition labels use Calories (kcal) and often report macros in grams per serving with different serving-size conventions than the EU's per-100g standard; India's ICMR-NIN also publishes its own reference energy intake tables, which run somewhat lower than US RDA figures for a given body size, reflecting differences in the reference population studied. If you're cross-referencing a food label from a different country, the calorie and gram figures are directly comparable — just check whether you're looking at "per serving" or "per 100g."
Worked example: a 30-year-old male, 75 kg, 178 cm, moderately active: BMR = 10×75 + 6.25×178 − 5×30 + 5 = 750+1,112.5−150+5 = 1,717.5 kcal. TDEE = 1,717.5 × 1.55 ≈ 2,662 kcal/day for maintenance. On a balanced macro split, that's roughly 200g protein, 266g carbs, and 89g fat per day (30/40/30 by calories, converted at 4/4/9 kcal per gram).
Want a full protein/carb/fat breakdown with a diet-style toggle? Use the dedicated Macro Calculator. For the same number expressed as total daily burn including activity, plus cutting and bulking targets, see the TDEE Calculator. See what WHO's new GLP-1 obesity guideline actually says for the policy context behind medication-assisted weight management, or what it actually costs by country. Sleep matters too — try the Sleep Cycle Calculator. Splitting those calories into macronutrients? The Fat Intake Calculator converts a calorie target into grams of fat and shows the saturated fat ceiling. Alcohol calories are a separate question — see the Blood Alcohol Calculator. Weighing ingredients to log them accurately? The Cooking Measurement Converter turns cups into grams for each ingredient. Harris-Benedict and Mifflin-St Jeor both expect kilograms — convert with the kg to pounds converter if you weigh in pounds.