To calculate your macros, you work out how many calories you burn in a day, adjust that for your goal, and split the result into protein, fat and carbs. It takes about ten minutes with a calculator and your height, weight and age.
Treat the result as a starting point. Every formula gives an estimate, and your body may run a little higher or lower. Start close, track for a few weeks, and adjust based on what happens.
If you'd rather skip the math, our free Macro, TDEE & BMR Calculator does every step below for you.
Step 1: Estimate your resting calories (BMR)
Your basal metabolic rate, or BMR, is the number of calories your body burns at rest to keep your heart, lungs and organs working. The most common way to estimate it is the Mifflin-St Jeor equation. A review of the main formulas found it was the most accurate one for most adults.
- Men: BMR = (4.54 × weight in pounds) + (15.88 × height in inches) − (5 × age) + 5
- Women: BMR = (4.54 × weight in pounds) + (15.88 × height in inches) − (5 × age) − 161
The original equation uses kilograms and centimeters (10 × weight in kg + 6.25 × height in cm). The versions above give the same answer in pounds and inches.
Step 2: Multiply by your activity level (TDEE)
Your total daily energy expenditure, or TDEE, is everything you burn in a day: at rest, moving around, training and digesting food. To estimate it, multiply your BMR by the number that matches a normal week for you:
| Activity level | What it looks like | Multiply BMR by |
|---|---|---|
| Sedentary | Desk job, little exercise | 1.2 |
| Lightly active | Light exercise 1 to 3 days a week | 1.375 |
| Moderately active | Training 3 to 5 days a week | 1.55 |
| Very active | Hard training 6 to 7 days a week | 1.725 |
| Extra active | Physical job plus daily training | 1.9 |
Most people pick a level that's too high. If you're stuck between two, pick the lower one. If you lose weight faster than you expected, you can add calories later.
Step 3: Adjust for your goal
- To lose fat, eat about 10 to 20% below your TDEE. For most people that's 300 to 500 calories a day, which works out to losing about 0.5 to 1% of your body weight a week.
- To maintain, eat at your TDEE.
- To build muscle, eat about 5 to 10% above your TDEE. A small surplus gives you enough to build muscle without adding much fat.
Step 4: Set protein first
Protein comes first because it protects your muscle when you're eating less and helps you build it when you're eating more. A large review of resistance training studies found that protein's benefits leveled off at about 0.73 grams per pound of body weight a day (1.6 grams per kilogram), and some people kept benefiting up to about 1.0 gram per pound (2.2 grams per kilogram).
If you lift, 0.7 to 1.0 gram per pound (1.6 to 2.2 grams per kilogram) is a good target. Protein has 4 calories per gram, so multiply your grams by 4 to get the calories.
You set protein from your body weight instead of as a percentage of your calories. If it were a percentage, your protein would drop every time you cut calories, and that's when you most want to keep it high to hold on to muscle.
Step 5: Set fat
Your body needs some fat for hormones and to absorb certain vitamins, so fat has a floor. A good range is 20 to 35% of your total calories, which matches what the National Academies recommend for adults. Fat has 9 calories per gram, so divide the calories by 9 to get grams.
Step 6: Fill the rest with carbs
Whatever calories are left go to carbs, your main fuel for training. Subtract your protein and fat calories from your total, then divide by 4.
A worked example
Say you're a 30-year-old man who's 5 ft 10 in (178 cm), weighs 176 lb (80 kg), works out four days a week and wants to lose fat.
- BMR: (4.54 × 176) + (15.88 × 70) − (5 × 30) + 5 = about 1,765 calories
- TDEE: 1,765 × 1.55 = about 2,735 calories
- Goal: about 15% below TDEE = about 2,300 calories a day
- Protein: 0.8 g per pound × 176 lb = about 140 g, which is 560 calories
- Fat: 25% of 2,300 = 575 calories, which is about 64 g
- Carbs: 2,300 − 560 − 575 = 1,165 calories, which is about 291 g
| Daily target | Grams | Calories |
|---|---|---|
| Protein | 140 g | 560 |
| Fat | 64 g | 575 |
| Carbohydrates | 291 g | 1,165 |
| Total | 2,300 |
How to adjust after you start
Give it two to three weeks before you change anything. Weigh yourself three or four mornings a week and compare weekly averages, because your weight goes up and down from day to day with water and salt.
- If you're losing faster than planned, or your workouts feel flat, add 100 to 200 calories, mostly from carbs.
- If you haven't lost anything after three weeks, cut 100 to 200 calories from carbs or fat.
- Keep protein the same. It's the number that protects your muscle, so it's the one you change least.
Recalculate from scratch about every 10 to 15 lb (4.5 to 7 kg) you gain or lose, because your body burns a different amount at a different weight.
Common mistakes
- Overestimating your activity. A desk job plus four workouts a week counts as "moderately active" for most people, not "very active."
- Forgetting the small stuff. Cooking oil, sauces, coffee creamer and drinks can add 200 to 400 calories a day without you noticing.
- Changing your targets too often. If you change them every few days, you can't tell what's working.
- Not eating enough protein. It's easy to come in well under your target until you plan some protein into every meal.
Common questions
How accurate are macro calculators?
They give you an estimate. Even the best formula can be off by around 10% for any one person, which means the first few weeks of tracking and adjusting matter more than the number you start with.
Do women calculate macros differently?
The steps are the same. The Mifflin-St Jeor equation uses a different number at the end for women (−161 instead of +5), and protein is still based on body weight.
Is it better to count macros or calories?
Calories set whether you gain or lose weight. Macros, protein in particular, affect how much of that change is fat and how much is muscle. Counting macros covers both. For more on what each macro does, see What are macros?
How much protein do I need if I don't lift weights?
The official minimum of about 0.36 grams per pound (0.8 grams per kilogram) covers your basic needs. If you're active, like a runner or cyclist, you'll probably do better closer to 0.55 to 0.65 grams per pound (1.2 to 1.4 grams per kilogram).
Do I count fiber in my carbs?
In the U.S., nutrition labels include fiber in total carbohydrates, and most tracking apps count total carbs too. Tracking total carbs keeps your numbers matching the labels.
Sources
- Mifflin M.D. et al. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition (1990).
- Frankenfield D. et al. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. Journal of the American Dietetic Association (2005).
- Morton R.W. et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength. British Journal of Sports Medicine (2018).
- National Academies of Sciences, Engineering, and Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005).
