How to use the Macro Calculator
- Enter your daily calorie target — from a TDEE calculation, adjusted for your goal.
- Enter body weight, which anchors the protein target.
- Choose a goal: fat loss, maintenance or muscle gain.
- Read the gram targets and check they add back to your calorie figure.
How the calculation works
Protein is set first, from body weight rather than from a percentage of calories, because its requirement does not shrink when calories do — roughly 1.6 to 2.2 g per kilogram for people training with resistance. Fat is set next, with about 0.6 to 1.0 g per kilogram as a practical floor for hormone production and fat-soluble vitamin absorption. Carbohydrate takes whatever calories remain, which makes it the lever that moves with training volume.
The energy values used are 4 calories per gram of protein and carbohydrate and 9 per gram of fat. Because fat is more than twice as calorie-dense, small changes in fat grams shift the carbohydrate allowance considerably — one reason low-fat and low-carb plans can hit the same calorie total by very different routes.
Protein g = weight × 1.6–2.2 ; Fat g = weight × 0.6–1.0 ; Carbs g = (calories − 4×protein − 9×fat) / 4Source: International Society of Sports Nutrition position stands on protein and nutrient timing; Atwater energy factors (4/4/9 kcal per gram).
Worked example
A 71 kg lifter cutting on 2,050 calories per day.
- Protein at 2.0 g/kg = 142 g → 568 calories.
- Fat at 0.8 g/kg = 57 g → 513 calories.
- Remaining calories = 2,050 − 568 − 513 = 969.
- Carbohydrate = 969 / 4 ≈ 242 g.
Targets of roughly 142 g protein, 57 g fat and 242 g carbohydrate — about 28% protein, 22% fat, 47% carbohydrate.
Frequently asked questions
Do I need to hit the macros exactly every day?+
No. Protein is worth hitting closely; fat and carbohydrate can vary day to day as long as the weekly calorie total holds. Consistency across a week beats precision on any single day.
Is very high protein harmful?+
Intakes in the range these calculators suggest are well tolerated in healthy adults across the research. People with existing kidney disease should follow clinical advice rather than a general formula.
Should carbs go up on training days?+
Cycling carbohydrate higher on hard sessions and lower on rest days is a reasonable refinement once the weekly total is under control. It is optimisation, not a requirement for progress.
Does fibre count towards carbohydrate?+
On most labels yes, though fibre yields far less usable energy. If you are tracking net carbs, subtract fibre — just apply the same convention consistently so your totals stay comparable.
Last reviewed August 31, 2026. We review this page whenever the underlying formula, tax year, published rate or standard changes.