FitCalc

How to Calculate Macros (Step by Step)

Counting macros is choosing how your daily calories are divided between protein, carbohydrate and fat. This guide shows the arithmetic, the common splits and how to set priorities when you cannot hit every number exactly.

Quick answer: Protein and carbohydrate supply 4 kcal per gram; fat supplies 9. Set protein first from body weight (1.6–2.2 g/kg), set fat at a minimum (about 0.6–1 g/kg), then give the remaining calories to carbohydrate and divide by their energy values.

The energy values

Every macro calculation rests on three numbers: protein 4 kcal/g, carbohydrate 4 kcal/g, fat 9 kcal/g. From a calorie target, the share assigned to each macro is converted to grams by dividing by the relevant value.

A worked example

Take 2,200 kcal with a 30/40/30 split. Protein: 30% of 2,200 is 660 kcal, divided by 4, gives 165 g. Carbohydrate: 40% of 2,200 is 880 kcal, divided by 4, gives 220 g. Fat: 30% of 2,200 is 660 kcal, divided by 9, gives about 73 g.

Protein first

Protein has the strongest evidence for body composition, so set it from body weight rather than as a percentage. For general health 1.2–1.6 g/kg; for building muscle 1.6–2.2 g/kg; during a fat-loss diet 1.6–2.4 g/kg to protect muscle. Spread it across three to five servings of roughly 0.3–0.4 g/kg.

Fat as a minimum, carbs as the remainder

Fat supports hormones and vitamin absorption, so keep a floor of roughly 0.6–1 g/kg. Carbohydrate is the flexible macro: assign it whatever calories are left after protein and fat, which naturally means more carbs on training days and fewer on rest days.

Common splits

Balanced (30/40/30), low carb (35/25/40), high protein (40/35/25), keto (25/5/70) and endurance (25/55/20) are the main patterns. None is uniquely best; adherence matters more than the exact ratio, and protein should stay high in all of them.

When you cannot hit every number

Prioritise in order: hit your protein, keep calories within about 100 kcal of target, and let carbohydrate and fat trade off within the budget. Logging apps make this easy once the targets are set.

Frequently Asked Questions

How do I calculate macros from calories?
Choose a percentage split, multiply the calorie target by each share, then divide protein and carbs by 4 and fat by 9. The macro calculator does this and also gives grams per kilogram.
What is the best macro ratio for weight loss?
One that keeps protein high — about 40% or 2 g/kg — so muscle is preserved. The rest can be split by preference. The calorie deficit decides the loss, not the ratio.
Do I need to count macros to lose weight?
No. Controlling calories and eating enough protein covers most of the benefit. Macro counting adds precision for people who want it or who have plateaued.
What about alcohol?
Alcohol supplies about 7 kcal per gram and no useful macros. It fits within a calorie budget but should be counted against total intake, and it can blunt muscle protein synthesis if heavy.

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