Calories decide whether you gain or lose weight — macros (protein, carbohydrates and fat) decide what that weight is made of. Enter your daily calorie target and your goal, and this calculator splits it into grams of protein, carbs and fat per day.
Macro Calculator
Estimate only — not medical advice.
How the Macro Calculator Works
Each macronutrient provides a fixed amount of energy: protein 4 kcal per gram, carbohydrates 4 kcal per gram, and fat 9 kcal per gram. The calculator splits your calories by goal:
- Cut (lose fat): 40% protein / 30% carbs / 30% fat — high protein protects muscle in a deficit.
- Maintain: 30% protein / 40% carbs / 30% fat — a balanced default.
- Bulk (gain muscle): 30% protein / 45% carbs / 25% fat — extra carbs fuel training and recovery.
Worked Example
At 2,400 kcal with a cutting split (40/30/30): protein = 2,400 × 0.40 ÷ 4 = 240 g, carbs = 2,400 × 0.30 ÷ 4 = 180 g, fat = 2,400 × 0.30 ÷ 9 = 80 g.
How Much Protein Do You Really Need?
Research consistently shows that around 1.6–2.2 g of protein per kg of body weight per day is enough to maximise muscle growth and retention for people who train. If the optional body-weight field is filled in, this calculator shows your protein result in g/kg so you can check it against that range.
Frequently Asked Questions
What are macros?
Macros — short for macronutrients — are protein, carbohydrates and fat: the three nutrients that provide your calories.
Which macro split is best for fat loss?
The cutting split (40% protein, 30% carbs, 30% fat) works well for most people because higher protein reduces hunger and protects muscle. The best split, though, is the one you can follow consistently.
Do I need to hit my macros exactly every day?
No. Aim to be within about 5–10 g of each target, and judge your week as a whole rather than stressing over a single day.
Should I count fibre in my carbs?
Fibre is included in total carbohydrates on food labels. Count your total carbs as labelled and you will be consistent.