How to calculate macros
Multiply your daily calories by each percentage, then divide by the calories in a gram: 4 for protein, 4 for carbohydrate and 9 for fat. A 2,000 kcal day at 20, 50 and 30 percent is 100 g protein, 250 g carbs and 67 g fat.
Updated 21 October 2026. Sources named on the page.
- Three steps from calories to grams
- The 4, 4 and 9 kcal per gram rule
- A worked example you can check
- A planning tool, not a prescription
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Let the calculator do it
Enter your calories, choose a split or set your own percentages, and get grams of each.
The sums
Grams = daily kcal x share / kcal per gram. Protein and carbohydrate give 4 kcal a gram, fat gives 9.
2,000 kcal at 20 percent protein, 50 percent carbohydrate and 30 percent fat
| Macro | Calories | Working | Grams |
|---|---|---|---|
| Protein | 400 kcal | 400 / 4 | 100 g |
| Carbohydrate | 1,000 kcal | 1,000 / 4 | 250 g |
| Fat | 600 kcal | 600 / 9 | 66.7 g |
Sources: Energy values per gram of protein (4 kcal), carbohydrate (4 kcal) and fat (9 kcal) are the standard Atwater figures
Figures and sources checked 21 October 2026. General information, not medical advice.
Step 1: choose your calories
Start from a daily calorie target. If you do not have one, the calorie calculator will give you an estimate.
Step 2: choose a split
Pick percentages for protein, carbohydrate and fat that add to 100. A common balanced split is 20, 50 and 30. Other splits suit other tastes, and none is the single right answer.
Step 3: turn it into grams
Multiply calories by each percentage to get calories per macro, then divide protein and carbohydrate by 4 and fat by 9.
A note on kilojoules
If your target is in kilojoules, divide by 4.184 first to get kcal.
Limits
A split is a planning tool. It is for healthy adults and is not medical or dietary advice. A dietitian can tailor it to your needs.
Questions
How many calories are in a gram of each macro?
Protein and carbohydrate have 4 kcal a gram and fat has 9 kcal a gram.
What macro split is best?
There is no single best split. It depends on your preferences and needs, and a dietitian can help you choose.
Do my percentages have to add to 100?
Yes. The calculator asks for three shares that total 100.
Do I need to hit macros exactly?
No. Daily amounts vary, and being close over a week is enough for most people.
Keep going
Log what you eat against the grams
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