TDEE & BMR Calculator — educational

Type sex, age, weight, and height, pick an activity level and a goal, and read off three cards in real time: BMR (the Mifflin-St Jeor 1990 formula), TDEE (BMR times your activity multiplier), and a macro split (protein, fat, carbs in grams and kilocalories). Pure math in your browser, no upload, works offline once loaded.

Units
Used by the Mifflin-St Jeor coefficient (+5 male / −161 female).
years Slope: −5 kcal/day per year.
kg US mode uses pounds (lb); we convert internally to kg.
cm US mode uses total inches (e.g. 70 for 5′10″); we convert internally to cm.
Multipliers: 1.2 / 1.375 / 1.55 / 1.725 / 1.9 (Mifflin convention).
Drives the protein / fat / carb split and the deficit / surplus context line.

BMR — at complete rest

— kcal / day

TDEE — typical day

— kcal / day

Macro target — daily

— kcal / day

Deficit / surplus

— kcal / day

Daily macros

Protein

— g

— kcal (—%)

Fat

— g

— kcal (—%)

Carbs

— g

— kcal (—%)

Macro split

How the formulas work

BMR — the Mifflin-St Jeor equation (Am J Clin Nutr, 1990) estimates your resting energy expenditure from sex, age, weight, and height: 

Men:   10·kg + 6.25·cm − 5·age + 5
Women: 10·kg + 6.25·cm − 5·age − 161

TDEE multiplies that number by a standard activity factor (1.2 sedentary → 1.9 very active).

Macro split applies a 2026-friendly consensus heuristic (Helms / Aragon / Renaissance Periodization synthesis) — cuts skew higher-protein and lower-carb, bulks skew higher-carb. The goal label is a rough bracket, not a clinical prescription; for a personal plan talk to a registered dietitian.