What a macro calculator does
Calories tell you how much to eat. Macros tell you what that food is made of: protein, carbs and fat. This macro calculator takes a daily calorie target and splits it into grams of each, per day and per meal. If you do not know your calories, it estimates them from your sex, age, height, weight and activity level, then adjusts them for your goal, whether that is cutting, maintenance or bulking.
The formulas
Each macro provides a fixed amount of energy per gram. To turn a share of your calories into grams, divide by that number.
Example: 2,000 kcal at a balanced 30/40/30 split gives 2,000 × 0.30 ÷ 4 = 150 g protein, 2,000 × 0.40 ÷ 4 = 200 g carbs and 2,000 × 0.30 ÷ 9 = about 67 g fat. Spread over 3 meals, that is 50 g protein, about 67 g carbs and about 22 g fat per meal.
To estimate calories, the calculator uses the Mifflin-St Jeor equation for your resting energy (BMR) and multiplies it by an activity factor from 1.2 for a desk job to 1.9 for very hard daily training. Men: 10 × kg + 6.25 × cm − 5 × age + 5. Women: the same, minus 161 instead of plus 5.
Macro split presets
| Split | Protein | Carbs | Fat | Good for |
|---|---|---|---|---|
| Balanced | 30% | 40% | 30% | An easy default for most people and most goals. |
| High protein | 40% | 30% | 30% | Popular while cutting, to keep muscle and stay full. |
| Low carb | 40% | 20% | 40% | Fewer carbs, more fat, for people who feel better that way. |
| Keto (very low carb) | 25% | 5% | 70% | Very low carb. Talk to a doctor first if you have a medical condition. |
With the custom option you set your own percentages. They have to add up to 100%, and the calculator tells you when they do not. Keto is a very low carb diet, usually kept under about 20 to 50 g of carbs a day, and it is not right for everyone.
Protein by body weight
Many coaches set protein from body weight instead of a percentage, because your muscle needs do not shrink when you eat less. A common range for people who train is 0.7 to 1 g per pound of body weight, or 1.6 to 2.2 g per kg. Pick the protein by body weight option, set the grams per pound or kg and the share of calories from fat, and carbs fill whatever is left. If protein and fat already use up all your calories, the calculator asks you to lower one of them.
Cutting, maintenance and bulking
- Cutting (lose weight): about 20% under maintenance. Keep protein high so most of the loss comes from fat.
- Maintenance: eat what you burn. A good place to start if you want to recomp slowly or simply eat better.
- Bulking (gain weight): about 10% over maintenance, together with strength training, so most of the gain is muscle.
These are starting points. Track your weight for 2 to 3 weeks and adjust calories by 100 to 200 kcal if it moves too fast, too slow or in the wrong direction. This page is for information, not medical advice. If you are pregnant, have a medical condition or a history of disordered eating, work with a doctor or registered dietitian.
How to use the macro calculator
- 1Enter your daily calories, or let the calculator estimate them from your details, activity level and goal.
- 2Pick a macro split, set your own percentages, or choose protein by body weight.
- 3Choose 3, 4 or 5 meals and read your grams of protein, carbs and fat per day and per meal.
Frequently asked questions
What are macros?
Macros, short for macronutrients, are the three nutrients that provide calories: protein, carbohydrates and fat. Protein and carbs have about 4 kcal per gram, fat about 9 kcal per gram. Counting macros means aiming for a set number of grams of each per day instead of only counting calories.
Which macro split is best?
The best split is one you can stick with that gives you enough protein. For weight loss and fat loss, total calories matter most and higher protein helps you keep muscle. Balanced 30/40/30 is a fine default. Low carb and keto suit some people, but they are not required to lose weight.
How much protein do I need per day?
For active adults who train, a common target is 0.7 to 1 g of protein per pound of body weight, or 1.6 to 2.2 g per kg. Use the protein by body weight option to set it directly. People with kidney disease should ask their doctor before eating a high protein diet.
Should I hit my macros exactly every day?
No. Getting within about 5 to 10 g of protein and carbs and a few grams of fat is plenty. What counts is the average over a week. Hit your protein target most days and keep calories close, and the rest can move around.
How do I adjust my macros over time?
Weigh yourself a few times a week and compare weekly averages. If your weight does not move in the direction you want after 2 to 3 weeks, change calories by about 100 to 200 kcal, mostly from carbs or fat, and keep protein the same. Recalculate after a larger change in body weight.