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Macro Calculator

Turn a calorie target into grams of protein, carbohydrate and fat.

What this calculates

Calories decide whether your weight moves. Macros decide what you lose or gain while it does, and how the day feels while you are doing it. Protein is the one worth defending; carbohydrate and fat can shuffle around it to suit how you like to eat.

Common questions

Which macro matters most?

Protein, by a distance. In a deficit it is what keeps the weight you lose coming off fat rather than muscle, and it is the most filling of the three per calorie. Hit protein, keep calories in range, and the rest is preference.

Do I have to hit the numbers exactly?

No. Landing within about ten grams of protein and inside your calorie range is plenty. Chasing decimal precision on carbs and fat costs more attention than it returns.

Why does keto give such a small carb number?

A ketogenic diet works by keeping carbohydrate low enough that the body shifts to running largely on fat and ketones — usually under about 30–50 g a day. The calculator caps carbs at 30 g and lets fat take whatever is left after protein.

Is a plant-based split different?

The protein target is set a little lower per kilo because plant proteins are less completely absorbed and lower in leucine, and hitting a very high figure on plants alone gets hard. Spreading protein across more meals and combining sources closes most of the gap.

Estimates for healthy adults — not medical advice, diagnosis or treatment. If you are pregnant or breastfeeding, under 18, managing a condition such as diabetes or thyroid disease, or have a history of disordered eating, talk to a doctor or a registered dietitian before acting on any of this.

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Content last reviewed 29 August 2026. Estimates for healthy adults, not medical advice.