Macro calculator
Get your daily protein, carbohydrate and fat in grams, worked out from your bodyweight and calorie target rather than from a fixed percentage split.
Your details
Your daily macros
protein from bodyweight → fat from bodyweight → carbohydrate fills what is left
Free, no account, and it runs entirely in your browser.
How each macro is set
The order matters. Two of the three are anchored to your bodyweight, and carbohydrate takes whatever energy remains.
- Protein
1.8 g per kg, or2.0 g per kgwhen building muscle. Set first, because it is the one with the clearest floor.- Fat
0.8 g per kgof bodyweight. Enough to support hormone production and the absorption of fat-soluble vitamins, without crowding out the carbohydrate that fuels training.- Carbohydrate
- Whatever energy is left after protein and fat are covered, with a floor of
80 g. Carbohydrate is the most flexible of the three, so it absorbs the change when your calorie target moves.
carbohydrate = (daily calories − protein g × 4 − fat g × 9) ÷ 4
Protein and carbohydrate each supply about 4 kcal per gram, fat about 9.
Why carbohydrate is the remainder
Protein has a defensible minimum and fat has a sensible floor. Carbohydrate has neither in the same way: it is the lever you pull to change energy intake. Setting it as the remainder means your calorie target is always met exactly, and it is the reason the percentage split shifts as your goal changes rather than staying fixed.
This is also why fixed ratios such as 40/30/30 tend to fall apart in practice. At a low bodyweight and a large deficit they leave too little protein; at a high bodyweight they prescribe more fat than anyone needs.
About the 80 g carbohydrate floor
In an aggressive deficit at a heavy bodyweight, the arithmetic can leave very little room for carbohydrate. The floor stops the calculator returning a number that would make training miserable. If you hit it, the honest reading is that your deficit is too large for your bodyweight, not that you should eat 80 g of carbohydrate and hope.
Hitting the numbers without weighing everything
Get protein right first, keep fat roughly in range, and let carbohydrate land where it lands. Most people who track everything to the gram for a week discover their usual meals are already close, and the useful change is one or two swaps rather than a new diet.
Free, no account, and it runs entirely in your browser.