Calculator · Free, no signup
Macro
calculator
Enter your metrics and goal. We work out maintenance, adjust it, then split the calories protein-first — and show every step so you can check the arithmetic.
Why the order of operations matters
Most macro calculators hand you three percentages — 40/30/30 and similar — and divide your calories by them. That is backwards, and it produces targets that quietly fail at the extremes.
Protein and fat both have floors. Protein has one because below roughly 1.6 g per kilogram you start leaving muscle on the table, and in a deficit you start losing it. Fat has one because it is required for hormone production and for absorbing the fat-soluble vitamins. Carbohydrate has no floor in the same sense — it is fuel, and the body has other ways to make it.
So this calculator sets protein from your body weight, then fat with a floor of 0.6 g/kg that overrides the percentage when the two disagree, and gives what is left to carbohydrate. On a normal diet you will not notice the difference. On an aggressive cut for a heavy lifter, percentage-first maths returns a fat target low enough to matter.
Protein is the number worth getting right
Once calories and protein are matched, the carbohydrate-to-fat ratio has remarkably little effect on how much fat you lose. Trials that pit higher-carb against lower-carb diets under those conditions land in much the same place.
Which means the fat preference selector above is genuinely a preference. Pick the one you find easier to eat. Someone training hard five times a week usually feels better on more carbohydrate; someone who finds fat more satiating should take the lower-carb option. Neither is more correct.
Where the calorie number comes from
Everything here starts from maintenance, estimated with Mifflin-St Jeor and an activity multiplier. If you want to see that step on its own — including the Katch-McArdle alternative for lean and muscular people — theTDEE calculator shows it in isolation.
Remember that maintenance is an estimate with roughly a 10% error band. Run these macros for a fortnight, track your weekly average weight, and shift the calorie figure if reality disagrees with the equation. Reality wins.
Hitting the numbers
Protein is the target people miss, and they usually miss it before lunch. Anchor each meal to a protein source before you decide anything else on the plate — thehigh-protein meal templates are built around exactly that habit, and the protein guidecovers where the g/kg figures come from.
Common questions
How do I calculate my macros?
Start from your maintenance calories, adjust for your goal, then set protein from body weight, fat as a share of calories with a floor of about 0.6 g/kg, and give the remainder to carbohydrate. That order matters: protein and fat both have minimums below which something breaks, while carbohydrate is the flexible fuel.
What is the best macro split for fat loss?
There is no single best split once calories and protein are matched — trials comparing higher-carb and lower-carb diets at equal calories and protein find very similar fat loss. Pick the split you can actually stick to. Protein is the part worth getting right; the carb-to-fat ratio is largely preference.
How much protein should I eat when cutting?
Around 2.2 g per kilogram of body weight. In a deficit protein does double duty, preserving lean mass while you lose fat and keeping you fuller per calorie than carbohydrate or fat. The leaner you already are, the more it matters.
Do I need to hit my macros exactly every day?
No. Aim to land within about 5 grams on protein and let carbohydrate and fat float against each other to fill the calories. Weekly averages drive results; single days do not. Treating the numbers as hard targets is how tracking turns into a problem of its own.
Why is my fat target higher than the percentage I picked?
A floor of 0.6 g per kilogram of body weight overrides the percentage when the two conflict. On an aggressive deficit a percentage-based target can fall low enough to affect hormone production and the absorption of fat-soluble vitamins, so the floor wins.
Should I change my macros on rest days?
Not usually. Calorie cycling adds complexity for a benefit that is hard to detect in practice, and weekly totals are what drive the outcome. Keep protein constant every day and worry about the rest only if you are competing.