Macro Calculator
Find how many grams of protein, carbs and fat fit your daily calories, for losing, keeping or gaining weight.
Adds up to 100%
Carbs fill whatever calories are left.
How your macros are worked out
Your daily calories first, then shared out between protein, carbs and fat.
- 1
Resting burn
10×65 + 6.25×165
− 5×30 − 161
= 1,370 kcal - 2
Daily target
1,370 × 1.375
= 1,884
≈ 1,880 kcal - 3
Protein first
1,880 × 20% ÷ 4
= 94 g protein - 4
Carbs and fat
carbs 50%÷4 = 235 g
fat 30%÷9 = 63 g
Read more: the formula, a worked example and the usual ranges
"Macros" are the three nutrients that give food its calories: protein, carbohydrates (carbs) and fat. This calculator first estimates your daily calories the same way as our calorie calculator: your resting burn (BMR) by the Mifflin–St Jeor equation, times your activity level, then adjusted for your goal. It then shares those calories out between the three macros and turns them into grams. In Advanced you can change the formula, add your body fat, pick a diet style, set your own % split or use grams per kg, and choose how many meals you eat.
The formula
Daily calories = BMR × activity factor ± goal change
Protein grams = calories × protein % ÷ 4
Carb grams = calories × carb % ÷ 4
Fat grams = calories × fat % ÷ 9
BMR (Mifflin–St Jeor) = 10 × weight in kg + 6.25 × height in cm − 5 × age, then + 5 for men or − 161 for women
Protein and carbs give about 4 kcal per gram and fat about 9 kcal per gram (1 kcal = 4.184 kJ). The goal change is your weekly rate × 7,700 kcal per kg (or 3,500 kcal per lb) ÷ 7 days, so 0.5 kg a week is 550 kcal a day. With grams per kg, protein = grams per kg × your weight, fat = grams per kg × your weight, and carbs = (calories − protein × 4 − fat × 9) ÷ 4.
Worked example
A 30-year-old woman, 165 cm and 65 kg, with light exercise, who wants to stay at her weight. Her BMR is 10 × 65 + 6.25 × 165 − 5 × 30 − 161 = 650 + 1,031.25 − 150 − 161 = 1,370.25 kcal. Times 1.375 for light exercise gives 1,884.09, rounded to 1,880 kcal a day (about 7,870 kJ).
With the balanced split (20% protein, 50% carbs, 30% fat): protein 1,880 × 0.20 ÷ 4 = 94 g (376 kcal), carbs 1,880 × 0.50 ÷ 4 = 235 g (940 kcal) and fat 1,880 × 0.30 ÷ 9 = 62.7, about 63 g (564 kcal). 376 + 940 + 564 = 1,880. Over 3 meals that's about 31 g protein, 78 g carbs and 21 g fat each. The fibre guide is 14 × 1,880 ÷ 1,000 = 26.3, about 26 g a day.
Grams per kg instead: at 1.6 g protein and 0.8 g fat per kg, protein is 1.6 × 65 = 104 g (416 kcal) and fat is 0.8 × 65 = 52 g (468 kcal). Carbs get the rest: (1,880 − 416 − 468) ÷ 4 = 996 ÷ 4 = 249 g.
Diet styles (common splits)
| Style | Protein / carbs / fat |
|---|---|
| Balanced | 20% / 50% / 30% |
| Lower fat | 20% / 60% / 20% |
| Lower carb | 30% / 25% / 45% |
| High protein | 40% / 35% / 25% |
| Zone style | 30% / 40% / 30% |
| Keto style | 20% / 5% / 75% |
These are common splits used by macro calculators and diet plans, not medical advice. The Zone style is the 40% carbs, 30% protein, 30% fat pattern. Keto style keeps carbs very low (about 5%, usually under 50 g a day) so most energy comes from fat; it isn't right for everyone, so check with a doctor first if you take medicine or have a health condition.
Usual adult ranges
| Macro | Share of calories |
|---|---|
| Protein | 10–35% |
| Carbs | 45–65% |
| Fat | 20–35% |
These are the Acceptable Macronutrient Distribution Ranges from the US and Canadian Dietary Reference Intakes (National Academies). The calculator shows each range in grams for your calories. The lower carb, high protein and keto styles go outside them on purpose.
Protein, fibre, sugar and fat guides
The usual adult protein reference is 0.8 g per kg of body weight a day. Many sports nutrition sources suggest about 1.2–2.0 g per kg for people who train hard or are losing weight and want to keep muscle. The fibre guide of 14 g per 1,000 kcal comes from the Dietary Guidelines for Americans; the UK suggests 30 g a day for adults. The WHO suggests keeping free sugars and saturated fat each under 10% of your calories, shown here in grams.
These are estimates for healthy adults; real needs vary. They're not suitable for pregnancy, breastfeeding, under-18s or anyone with a medical condition (such as kidney disease or diabetes) or a history of eating disorders. This calculator won't suggest going below 1,200 kcal (women) or 1,500 kcal (men) a day. Talk to a doctor or registered dietitian before making big changes to how you eat.
Common questions
How do I calculate my macros?
First work out your daily calories, then share them between protein, carbs and fat. Protein grams = calories × protein % ÷ 4, carb grams = calories × carb % ÷ 4 and fat grams = calories × fat % ÷ 9. For 1,880 kcal with a 20/50/30 split, that's 94 g protein, 235 g carbs and about 63 g fat.
What is a good macro split for weight loss?
There's no single best split. A balanced split of 20% protein, 50% carbs and 30% fat sits inside the usual adult ranges. Many sports nutrition sources suggest more protein, about 1.2–2.0 g per kg of body weight, when you're losing weight and want to keep muscle.
How much protein do I need a day?
The usual adult reference is 0.8 g per kg of body weight a day. Many sports nutrition sources suggest about 1.2–2.0 g per kg for people who train hard or are losing weight and want to keep muscle. In Advanced you can set protein in grams per kg instead of a percentage.
How many calories are in a gram of protein, carbs and fat?
Protein and carbs give about 4 kcal per gram and fat gives about 9 kcal per gram. One kilocalorie is 4.184 kJ, so you can switch the calculator to kilojoules if your food labels use them. The calculator turns your calories into grams of each for you.
What are the usual macro ranges for adults?
The US and Canadian Dietary Reference Intakes suggest about 10–35% of calories from protein, 45–65% from carbs and 20–35% from fat. The calculator shows each range in grams for your calories. The lower carb, high protein and keto styles go outside these ranges on purpose.
How much fibre should I eat a day?
The Dietary Guidelines for Americans suggest 14 g of fibre for every 1,000 kcal you eat, so 1,880 kcal a day works out to about 26 g. The UK suggests 30 g a day for adults. The calculator works out the fibre guide for your own calories.
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Made by Zulu Calculator, part of AlphaZulu LLC. Formulas are shown in full and rule figures are checked against official sources; see how we build calculators.