TDEE Daily Calorie, Macro Split & Hydration Intake Calculator

Calculate Your TDEE, Macros, and Daily Water Intake

“How much should I eat?” has a real mathematical answer, and it starts with two numbers: your BMR and your TDEE. Basal metabolic rate — estimated by the Mifflin-St Jeor equation from your weight, height, age, and sex — is what you’d burn lying still all day. Total daily energy expenditure multiplies that by an activity factor (1.2 for sedentary up to about 1.9 for heavy training). A 70 kg, 175 cm, 30-year-old man lands near 1,700 kcal BMR; moderately active, his TDEE is roughly 2,600. Eat below it to lose, above it to gain — the deficit or surplus, sustained, is the entire game.

Macros are how you split those calories so the weight you lose is fat, not muscle. Protein is the priority: roughly 1.6–2.2 grams per kilogram of body weight daily when training (a 70 kg lifter targets about 115–155 g). Fill the rest with carbs for training fuel and fats for hormones — at least 0.5 g/kg of fat — in whatever ratio you’ll actually sustain, because adherence beats optimal ratios every time. Then water: the old “eight glasses” rule ignores body size, so use 30–35 ml per kilogram instead — about 2.1–2.5 liters for that same 70 kg person, more in heat or hard training. Pale-yellow urine remains the cheapest hydration test ever invented.

The honest caveats matter more than the numbers. These equations estimate; real metabolisms vary 10–15% either way, so treat the output as a starting point and adjust after two to three weeks of tracking weight trends. Activity factors are the fuzziest input — most people overestimate, so when in doubt pick the lower tier. And no calculator replaces medical guidance: pregnancy, eating-disorder history, diabetes, or kidney issues mean checking with a clinician before acting on any of this. Used wisely, though, three personalized numbers beat a thousand generic diet tips.