How to use the Macro Calculator (Protein, Carbs, Fat)
- Enter your daily calorie target.
- Enter the percentages for protein, carbohydrate and fat. They must add up to 100.
- Enter how many meals you eat per day.
- Read the grams of each macro per day and per meal.
Formula used
Protein grams = calories × protein share ÷ 4. Carbohydrate grams = calories × carb share ÷ 4. Fat grams = calories × fat share ÷ 9. The three shares must add up to 100%.
Worked example
Here is the Macro Calculator (Protein, Carbs, Fat) worked through with the example values shown above, so you can check each step by hand.
| Inputs | |
|---|---|
| Daily calories | 2,000 kcal |
| Protein share | 30 % |
| Carbohydrate share | 40 % |
| Fat share | 30 % |
| Meals per day | 3 |
| Result | |
| Daily macros | 150 g protein · 200 g carbs · 67 g fat |
| Protein per day (g) | 150 |
| Carbohydrate per day (g) | 200 |
| Fat per day (g) | 66.666667 |
| Protein per meal (g) | 50 |
| Carbohydrate per meal (g) | 66.666667 |
| Fat per meal (g) | 22.222222 |
Grams per day at different calorie targets
For the default 30% protein, 40% carbohydrate and 30% fat split.
| Daily calories | Protein per day (g) | Carbohydrate per day (g) | Fat per day (g) |
|---|---|---|---|
| 1,500 kcal | 112.5 | 150 | 50 |
| 1,800 kcal | 135 | 180 | 60 |
| 2,000 kcal | 150 | 200 | 66.666667 |
| 2,500 kcal | 187.5 | 250 | 83.333333 |
| 3,000 kcal | 225 | 300 | 100 |
The conversion
Protein and carbohydrate each provide about 4 calories per gram, and fat provides about 9. So with 2,000 calories and a 30/40/30 split, protein is 2,000 × 0.30 ÷ 4 = 150 g, carbohydrate is 2,000 × 0.40 ÷ 4 = 200 g and fat is 2,000 × 0.30 ÷ 9 = 66.7 g.
Over three meals that is about 50 g of protein, 67 g of carbohydrate and 22 g of fat per meal.
Trying other splits
A higher-protein split of 40/30/30 on the same calories gives 200 g protein, 150 g carbohydrate and 67 g fat. A lower-carbohydrate 30/20/50 split gives 150 g, 100 g and 111 g.
Because fat is so energy dense, shifting percentage points to fat reduces the grams by more than shifting the same points to carbohydrate would add.
Choosing a split
There is no single best split. Common starting points are about 10 to 35% of calories from protein, 45 to 65% from carbohydrate and 20 to 35% from fat, which are the ranges published in US dietary guidelines for adults. Athletes, people with diabetes and others may need something different.
Preferences, appetite and how you feel matter as much as the numbers. A registered dietitian can set a split suited to your health and goals.
Practical tips
Food labels and tracking apps show grams, so this calculator gives you targets in the same terms. Weigh food, track for a week, and adjust based on hunger, energy and progress rather than trying to hit the figure exactly every day.
Alcohol provides about 7 calories per gram and is not counted here, and fibre and sugar alcohols are counted differently on some labels, so small differences are normal.
Frequently asked questions
How many calories are in a gram of each macro?
About 4 for protein, 4 for carbohydrate and 9 for fat.
Why must the percentages add up to 100?
Because together they account for all of your calories. The calculator tells you if they do not.
What macro split should I use?
It depends on your goals, health and preferences. A dietitian can advise on a split for you.
Do I need to hit the grams exactly?
No. Treat them as targets and aim to be close on average over a week.
How do I find my calorie target?
Use the calorie calculator on this site, which estimates daily calories from age, sex, height, weight and activity.
Does this account for fibre or alcohol?
No. It uses the simple 4-4-9 conversion, so labels may differ slightly.
This calculator gives estimates for information only. Actual figures from a bank, employer, tax authority or doctor may differ. It is not financial, tax, legal or medical advice.