Macro Calculator
Get your daily calorie target and exact macronutrient breakdown — protein, carbs, and fat — based on your body stats, activity level, and goal.
Example result
Male · 30 · 80 kg · 180 cm · Moderately active · Maintain
2759 kcal / day
Protein 160 g · Carbs 357 g · Fat 77 g
How this macro calculator works
The calculation runs in three steps: BMR → TDEE → macro split.
Step 1 — Basal Metabolic Rate (BMR)
BMR is the calories your body burns at complete rest. This calculator uses the Mifflin-St Jeor equation, the most accurate formula for the general population:
Women: BMR = 10 × kg + 6.25 × cm − 5 × age − 161
Step 2 — Total Daily Energy Expenditure (TDEE)
TDEE multiplies your BMR by an activity factor that accounts for exercise and daily movement. This is the number of calories you burn in a typical day:
Eating at your TDEE maintains your current weight. A sustained deficit causes fat loss; a sustained surplus enables muscle gain.
Step 3 — Macro split
Once calories are set, macronutrients are distributed as follows:
- Protein: 2.0g per kg of bodyweight — near the top of the 1.6–2.2 g/kg range that research links to muscle gain
- Fat: 25% of total calories ÷ 9 (calories per gram of fat)
- Carbs: remaining calories ÷ 4 (calories per gram of carbohydrate)
Read the full science behind protein targets in our guide: How much protein per day to build muscle?
Track macros and earn buffs in GYM RPG
GYM RPG's nutrition tracker lets you log meals by searching foods and saving favourites; the barcode scanner is part of Pro. Log food with calories on consecutive days to build a nutrition streak that boosts the XP and stats you earn from workouts.
Sources (checked 2026-10): Mifflin MD, St Jeor ST, et al. Am J Clin Nutr 1990;51:241-247, doi:10.1093/ajcn/51.2.241; Morton RW, Murphy KT, et al. Br J Sports Med 2018;52:376-384, doi:10.1136/bjsports-2017-097608.
Meal logging and the nutrition streak bonus are free on iOS & Android. The barcode scanner is Pro.
Frequently asked questions
How accurate is this macro calculator?
The Mifflin-St Jeor equation is the most validated BMR formula for the general population, with studies showing ±10% accuracy for most people. Actual needs vary with muscle mass, hormones, and individual metabolism — use the result as a starting point and adjust based on 2–3 weeks of real-world data.
How much protein do I actually need to build muscle?
Research consistently supports 1.6–2.2g of protein per kg of bodyweight per day for maximising muscle protein synthesis. This calculator uses 2.0g/kg as a reliable target for active lifters. Distribution matters too — aim for 3–5 meals with at least 30–40g protein each.
What is TDEE?
TDEE stands for Total Daily Energy Expenditure — the total calories you burn in a day including your basal metabolic rate (BMR), exercise, and the thermic effect of food. Eating at your TDEE maintains weight; a deficit causes fat loss; a surplus enables muscle gain.
How large should my calorie deficit be for fat loss?
A 300–500 calorie daily deficit produces 0.3–0.5 kg of fat loss per week — the rate that best preserves muscle. Larger deficits increase muscle loss, drop training performance, and are harder to sustain. This calculator uses a 400 calorie deficit for the cut setting.
Should I eat the same macros on rest days?
For most people, keeping macros consistent 7 days a week is simpler and works just as well as carb cycling. If you prefer, reduce carbs by 50–100g on rest days and add them back on training days — but the total weekly intake matters more than daily variation.