Macro Calculator
A macro calculator turns a daily calorie target into grams of protein, carbohydrate, and fat by splitting those calories across a chosen diet ratio. This tool offers four presets — Balanced (30/40/30), Low Carb (40/25/35), High Protein (40/30/30), and Keto (30/5/65) — and converts each slice of calories into grams using 4 calories per gram for protein and carbs and 9 per gram for fat. The result tells you not just how much to eat, but the shape of those meals.
Formula
grams = (calories × percent / 100) ÷ caloriesPerGram
- calories
- Your daily calorie target
- percent
- Share of calories for that macro (e.g. Balanced: 30% protein, 40% carb, 30% fat)
- caloriesPerGram
- Energy density: 4 for protein, 4 for carbs, 9 for fat
How it works
- Enter your daily calorie target (often taken from a TDEE or calorie calculator) and pick one of the four diet presets.
- Each macro’s percentage is multiplied by your calorie target to get the calories from that macro.
- Those macro calories are divided by their energy density — 4 cal/g for protein and carbohydrate, 9 cal/g for fat — to give grams per day for each.
Worked examples
A 2,000-calorie day on the Balanced preset (30% protein, 40% carbs, 30% fat).
- Protein: 2000 × 0.30 = 600 cal ÷ 4 = 150 g.
- Carbs: 2000 × 0.40 = 800 cal ÷ 4 = 200 g.
- Fat: 2000 × 0.30 = 600 cal ÷ 9 = 66.7 g.
150 g protein, 200 g carbs, and about 67 g fat per day.
The same 2,000 calories on the Keto preset (30% protein, 5% carbs, 65% fat).
- Protein: 2000 × 0.30 = 600 cal ÷ 4 = 150 g.
- Carbs: 2000 × 0.05 = 100 cal ÷ 4 = 25 g.
- Fat: 2000 × 0.65 = 1300 cal ÷ 9 = 144.4 g.
150 g protein, 25 g carbs, and about 144 g fat — the high-fat, very-low-carb keto shape.
Frequently asked questions
- Why is fat 9 calories per gram but protein and carbs only 4?
- Those are the standard Atwater energy values: each gram of fat releases about 9 calories when metabolised, while protein and carbohydrate yield roughly 4 each. That is why a keto plan has far fewer grams of fat than its high calorie share might suggest.
- Where do I get the calorie number to enter?
- Use your maintenance calories from a TDEE calculator, then add or subtract roughly 500 calories per day to gain or lose about a pound a week. The macro calculator simply distributes whatever total you provide.
- Which macro split is best for me?
- It depends on your goals and preferences. Balanced suits most people, higher-protein splits help preserve muscle while dieting, and keto drives carbs very low for those who prefer it. All four presets here hit the same calorie total.
- Do the grams need to be exact every day?
- No. These are daily averages, and hitting them closely over a week matters more than matching every gram at every meal. Protein is usually the one worth tracking most carefully.