Macros Calculator

How calories become grams

Each macronutrient provides a fixed amount of energy:

The calculator applies a balanced split of 30% protein, 40% carbohydrates and 30% fat, then divides each share by its energy per gram.

Worked example

For 2,000 kcal a day:

• Protein: 2,000 × 30% = 600 kcal ÷ 4 = 150 g
• Carbohydrates: 2,000 × 40% = 800 kcal ÷ 4 = 200 g
• Fat: 2,000 × 30% = 600 kcal ÷ 9 = 67 g

At 2,500 kcal the same split gives 188 g of protein, 250 g of carbohydrates and 83 g of fat.

Is 30/40/30 right for you?

The split sits inside the ranges generally recommended for adults — about 10–35% of energy from protein, 45–65% from carbohydrates and 20–35% from fat — while being on the high side for protein, which helps with satiety and muscle maintenance. You may want to adjust it:

• Protein is best set per kilo of body weight. The general recommendation is 0.8 g/kg; people who train regularly often aim for 1.2–2.0 g/kg. A 70 kg person training hard would target about 85–140 g.
• Endurance athletes usually need more carbohydrates (50–60% of energy) to fuel long sessions.
• Lower-carbohydrate diets shift energy toward fat; this is a personal choice rather than a requirement for weight loss — total calories matter most.

Practical tips

Start by finding your calorie target with the daily calorie calculator, then use these grams as a guide rather than a strict rule. Hitting your protein target and staying close to your total calories matters far more than splitting carbohydrates and fat to the gram. Food labels list grams of each macronutrient per 100 g, which makes tracking straightforward.

Formulas and content last reviewed: October 2026 · About