Macro & Calorie Calculator
Set your calorie target from a published BMR equation, then split it into protein, carbohydrate and fat — by percentage or in grams.
- 01Enter your details. Body fat is optional but improves accuracy noticeably.
- 02Pick a goal. Cut targets a moderate 20% deficit, Maintain stays at estimated maintenance, and Gain targets a 10% surplus.
- 03Adjust the macro split by typing percentages or grams — either unit works.
What the terms mean
- Macros
- Protein, carbohydrate and fat — the three nutrients that supply energy.
- BMR
- Basal metabolic rate: the energy your body uses at complete rest.
- TDEE
- Total daily energy expenditure: BMR plus everything else you do.
- Lean body mass
- Everything that is not fat — muscle, bone, organs, water.
Unlocks lean-mass protein and Katch-McArdle.
To maintain — at maintenance.
Method & sources
Energy uses the Mifflin-St Jeor equation, multiplied by an activity factor for TDEE. Protein is set from body weight (≈1.8 g/kg), fat is floored at 0.8 g/kg for hormonal health, and carbohydrate fills the remainder.
Mifflin MD et al., Am J Clin Nutr 1990 · Roza & Shizgal 1984 · Katch & McArdle · Cunningham 1980 · Helms ER et al., The Muscle and Strength Pyramid
What these numbers
actually tell you.
The calorie number is a starting point, not a prescription
It comes from an equation fitted to population averages, and individual expenditure varies by several hundred calories a day at the same height and weight. Run this target for two to three weeks, track a weekly average bodyweight, then adjust by 100–200 kcal based on what actually happened.
Protein first, then fat, then carbohydrate
Protein is set from lean mass when you supply body fat, because fat tissue contributes almost nothing to protein requirement. Fat is floored at 0.8 g/kg for hormonal health. Carbohydrate fills whatever calories remain, which is why it moves most when you change the split.
What to do if the totals turn red
The calculation still runs — nothing breaks. Red means your split exceeds 100% (or your calorie target, in grams mode). Either reduce one macro or accept that you are planning to eat above your target, deliberately.
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