Calculate
Macro calculator
Energy from the Mifflin-St Jeor equation, or from Katch-McArdle when you know your body fat percentage — then protein, carbohydrate, fat, fibre and water for the goal you pick. It runs entirely in your browser and nothing you enter is sent anywhere.
Inputs
Your numbers.
Unlocks the lean-mass equation.
Adds a timeline and projection.
Daily targets
The plan.
2,740
kcal / day
BMR 1,768 · TDEE 2,740 kcal
- Protein
- 144 g · 576 kcal · 21%
- Carbs
- 370 g · 1,480 kcal · 54%
- Fat
- 76 g · 684 kcal · 25%
- Fiber
- 38 g
- Water
- 2.8 L
- Est. weekly change
- +0.00 kg / week
These figures are estimates from population prediction equations. Individual requirements vary substantially with genetics, medical history and training. This is educational information, not medical or dietetic advice.
Methodology
Where these numbers come from
Resting energy comes from the Mifflin-St Jeor equation, which is the prediction equation most widely used in practice. When you supply a body fat percentage the calculator switches to Katch-McArdle, which works from lean mass instead — a better estimate when lean mass is actually known, and the panel tells you which one it used.
Total expenditure multiplies that by an activity factor. This is the least precise step by a wide margin: non-exercise activity varies enormously between similar people, and in one overfeeding study fat gained varied roughly ten-fold with that component. Treat the multiplier as a starting guess.
Protein targets follow the ranges reported in the pooled resistance-training literature and the professional society position stand, set higher during a deficit where protein protects lean tissue. Where body fat is known, protein is scaled to lean mass instead of total bodyweight.
Fibre uses 14 g per 1,000 kcal, the basis of the US dietary reference intake. Weekly change assumes roughly 7,700 kcal per kilogram of body tissue — a serviceable approximation that is least accurate in the first two weeks, when much of the change on the scale is water and glycogen rather than fat.
Every one of these is a population estimate. Two people with identical inputs can have genuinely different requirements, and the honest way to use a calculator like this is as a starting point — one you adjust against what actually happens over three or four weeks.
This section is educational reference material for general audiences. It is not medical or dietetic advice, it is not tailored to anyone’s circumstances, medical conditions, allergies or medication, and it is not a substitute for a qualified professional. Figures reported here describe what the cited research measured in the populations it studied — individual requirements vary substantially. Nothing here relates to the use of any product sold on this site.