Macro Calculator
Estimate how many grams of protein, carbs and fat to eat each day for your goal, and what share of your calories each one is. The math runs in your browser: nothing you type is sent anywhere.
Carbs never go below 50 g a day.
Your estimated macros
Fill in the form and press Calculate to see your daily calories and macros, in grams and as a percentage of calories.
- Calories
- Protein
- Fat
- Carbs
These are estimates, not medical or dietary advice. How we estimate, with sources
How this macro calculator works
It starts with calories. Your resting energy (BMR) comes from the Mifflin-St Jeor equation, using your sex, age, height and weight. Multiplying it by an activity factor for your training days gives your total daily energy (TDEE): 1.3 for 0–1 days a week, 1.45 for 2–3, 1.6 for 4–5 and 1.75 for 6–7.
Then your goal. To lose fat, the estimate aims at about 0.5% of your body weight a week; to build muscle, about 0.25% a week; to maintain, it stays at your TDEE. Rates use the common approximation of 7,700 kcal per kg, and the estimate never goes below 1,200 kcal or 1.2 times your BMR, whichever is higher.
Then the macros. Protein is 1.6 g per kg of body weight, or 1.8 g per kg to build muscle. Fat is 30% of calories (40% if you pick low carb), and carbs get the rest, never less than 50 g a day.
Macros for fat loss without losing muscle
When you eat less, part of the weight you lose can be muscle. Research on people lifting during a calorie deficit links more protein with keeping, and even gaining, lean mass. That is why the protein estimate here stays at 1.6 g per kg while you lose fat instead of dropping with your calories, and why the form asks how often you train.
Macros for women
Only the calorie step differs by sex. The Mifflin-St Jeor equation subtracts 161 kcal for women and adds 5 for men, so at the same age, height and weight a woman's resting energy estimate is 166 kcal a day lower. Protein, fat and carbs then follow the same rules for everyone, scaled to body weight and calories.
Macros for muscle gain
Pick Build muscle and the estimate adds a small surplus, aimed at gaining about 0.25% of your body weight a week, and raises protein to 1.8 g per kg. Fat stays at 30% of calories and carbs take the extra calories.
Why your macros should change each week
Any formula is a starting point. Equations like Mifflin-St Jeor come close for many people but not for everyone, and your energy use shifts as your weight and training change. The BodyMacros app checks your weight trend and what you logged each week, then re-estimates your calories and macros and tells you why they moved.
Macros in grams vs percentages
Grams are what you log; percentages show the balance between them. To convert, multiply the grams by the calories per gram (4 for protein and carbs, 9 for fat) and divide by your daily calories. For example, 150 g of protein is 600 kcal, which is 30% of a 2,000 kcal day. The calculator shows both.
FAQ
How do I calculate my macros?
Start with calories: estimate your resting energy (BMR), multiply it by an activity factor to get your TDEE, then adjust for your goal. Set protein from your body weight (1.6 g per kg here, 1.8 to build muscle), set fat as a share of calories (30%), and give the remaining calories to carbs. The calculator above does all of it.
What should my macros be to lose weight?
There is no single right answer, so treat any number as an estimate. This calculator aims at losing about 0.5% of your body weight a week, keeps protein at 1.6 g per kg to help protect muscle, sets fat at 30% of calories and gives carbs the rest. Your weekly weight trend then shows whether to adjust.
How do I convert macros from grams to percentages?
Multiply each macro's grams by its calories per gram: 4 for protein, 4 for carbs and 9 for fat. Divide by your total daily calories and multiply by 100. For example, 70 g of fat is 630 kcal, about 32% of a 2,000 kcal day. The calculator shows grams and percentages side by side.
Do women need different macros?
In this calculator only the calorie estimate differs: Mifflin-St Jeor gives women a resting energy 166 kcal a day lower than men of the same age, height and weight. Protein, fat and carbs follow the same rules for everyone, scaled to body weight and calories. Your own needs can differ, so check the estimate against your weekly trend.
Are free macro calculators accurate?
They give a reasonable starting estimate, not a measurement. In a systematic review, the Mifflin-St Jeor equation predicted resting energy within 10% of the measured value in more people than other equations, but not in everyone. Following your weight for a few weeks and adjusting gets you closer, which is what the app does for you.
Why should my macros change every week?
Your energy use changes as your weight, training and daily activity change, and a formula cannot see those changes. Re-estimating each week from your real weight trend corrects the starting estimate. The BodyMacros app does this for you and tells you in plain words why each target moved.
What is the difference between a macro calculator and a calorie calculator?
A calorie calculator estimates how much to eat in total each day. A macro calculator starts from that same number and splits it into protein, fat and carbs, in grams and as a share of calories. Calories come first; the macros say where those calories come from.
What changes in a macro calculator for muscle gain?
Choosing Build muscle adds a small calorie surplus, aimed at gaining about 0.25% of your body weight a week, and raises protein from 1.6 to 1.8 g per kg. Fat stays at 30% of calories and carbs take the rest. The surplus is kept small on purpose, so the weekly gain stays slow.
Does the calculator show the macros of each food?
No. It estimates your total daily targets, not the macros in a given food. To see what each meal adds up to, log what you eat in the BodyMacros app: it looks up food values, scans barcodes and shows how much of each target is left for the day.
Track this in the app
Log your food and your lifts in one place. Your estimates adjust each week to how you eat and train.
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