How to Calculate Your Macros
Four steps from your height and weight to a daily protein, fat and carb target — with a worked example you can check the arithmetic on.
Contents
The whole method in one line: estimate the calories you burn at rest, multiply by how active you are, add or subtract for your goal, then set protein from your bodyweight, fix fat, and let carbs take whatever calories are left.
Nothing here needs a body fat percentage or a lab test. It takes about two minutes with a calculator, and the worked example below shows every number so you can check yours against it.
What a macro actually is
"Macros" is short for macronutrients — the three things in food that carry energy. Everything you eat is some combination of them, and each carries a fixed amount of energy per gram:
| Macronutrient | Per gram | Mainly does |
|---|---|---|
| Protein | 4 kcal | Builds and retains muscle; keeps you full |
| Carbohydrate | 4 kcal | Fuels training; the easiest lever to move |
| Fat | 9 kcal | Hormones and vitamin absorption |
Because the energy per gram is fixed, calories and macros are not two separate targets — hit your macros and you have hit your calories automatically. That is why the calculation below works out calories first and splits them afterwards, rather than the other way round.
Your BMR
Your basal metabolic rate is roughly what you would burn lying in bed all day — the cost of simply being alive. The standard estimate is the Mifflin-St Jeor equation, which needs only weight in kilograms, height in centimetres and age in years.
The two formulas differ by a flat 166 kcal, which is the average difference in lean mass between men and women of the same height and weight. It is an average, not a rule about you — which is the first reason to treat the final number as a starting point rather than a verdict.
Your activity multiplier
BMR only covers being alive. Multiplying it gives your TDEE — total daily energy expenditure, or what you actually burn in a normal day. Pick the row that matches how often you train:
| Training | Base multiplier |
|---|---|
| 0–1 sessions a week | 1.35 |
| 2–3 sessions a week | 1.45 |
| 4–5 sessions a week | 1.55 |
| 6–7 sessions a week | 1.65 |
Then add for everything outside training, which matters more than most people expect — the difference between a desk job and a job on your feet can be several hundred calories a day:
| Your days are | Add |
|---|---|
| Mostly sitting (desk job) | +0.00 |
| Light movement, some walking | +0.06 |
| On your feet most of the day | +0.12 |
Adjust for your goal
TDEE is maintenance — eat it and your weight holds. To change weight you shift it, and the size of the shift decides how fast and how comfortably that happens.
| Goal | Base change |
|---|---|
| Lose fat | −400 kcal |
| Maintain | 0 |
| Gain muscle | +300 kcal |
The gain figure is deliberately smaller than the loss figure. There is a ceiling on how fast you can build muscle, and eating far above it adds fat rather than speed. Then scale by the pace you want:
| Pace | Multiply by |
|---|---|
| Steady — slower, easier to stick to | 0.65 |
| Balanced | 1.00 |
| Aggressive — faster, harder to hold | 1.35 |
One guard rail worth applying: never set your target below your BMR. An aggressive cut on a light day can otherwise prescribe less than the body's resting cost, which is where people start losing strength and sleep rather than fat.
Split it into protein, fat and carbs
Now turn one calorie number into three gram numbers. Set protein and fat first — they are the two you should not cut into — and give carbs whatever is left.
- Protein: 2 g per kg of bodyweight. Enough to hold onto muscle while losing fat, and simple to remember. An 80 kg lifter eats 160 g.
- Fat: a fixed floor by goal. 50 g when cutting, 65 g maintaining, 80 g gaining. Below roughly 0.5 g/kg you start trading away hormone function for very little gain.
- Carbs: everything left over. Subtract the calories protein and fat account for, then divide by 4.
Deriving carbs rather than fixing them is what keeps the three numbers honest. If all three were set independently they would not add up to your calorie target, and you would be handed two goals that quietly contradict each other.
The app runs this whole calculation from your profile and updates it as your weight changes.
Open the appA full worked example
A 30-year-old man, 80 kg, 180 cm, training 4 times a week, desk job, wanting to lose fat at a balanced pace.
Four sessions a week puts him on the 1.55 base, and a desk job adds nothing:
Losing fat at a balanced pace is −400 × 1.00, so his daily target is 2759 − 400 = 2359 kcal. Protein is 2 × 80 = 160 g, and fat on a cut is 50 g. Those account for 640 + 450 = 1090 kcal, leaving 1269 kcal of carbs — about 317 g.
The app then splits that average across training and rest days, moving carbs toward the days he uses them:
His daily targets
| Day | kcal | Protein | Carbs | Fat |
|---|---|---|---|---|
| Training day (×4) | 2595 | 160 g | 376 g | 50 g |
| Rest day (×3) | 2044 | 160 g | 239 g | 50 g |
| Weekly average | 2359 | 160 g | 317 g | 50 g |
Notice the last row: four days at 2595 and three at 2044 average out to exactly 2359 — the target from before the split. That is the point of the next section.
Why training and rest days differ
Carbs are the macro you burn through when you train, so it makes sense to eat more of them on the days you do. But the swing has to be a redistribution, not an increase — otherwise "more on training days" is just eating more, and the deficit you calculated disappears.
The way to keep it honest is to fund training days out of rest days in proportion to how many of each you have. Someone training four days and resting three takes a little from each of the three to give to each of the four. Someone training six days has only one rest day to draw on, so the swing is necessarily smaller — and at seven days a week there is nothing to cycle against, so it correctly disappears.
Done that way the weekly total is unchanged whatever your split, which is why the example above averages back to 2359 exactly. If your own training and rest targets do not average back to your calorie goal, the cycling is adding calories rather than moving them.
Four mistakes that make the numbers wrong
- Eating back your workout calories. The most common one by far. Your activity multiplier already accounts for training — that is what the sessions-per-week question was for. Logging a session and then eating its calories counts the same training twice.
- Never recalculating. Protein comes from bodyweight and the multiplier from training frequency. Lose 5 kg or drop from five sessions to two and every number above is stale.
- Treating the output as measured fact. Mifflin-St Jeor is an estimate with real variation between individuals. If your weight has not moved in three weeks, believe the scale over the formula and adjust by 100–150 kcal.
- Chasing all three macros to the gram. Protein and total calories are worth being tight on. Carbs and fat can trade against each other freely — the precision implied by "317 g of carbs" is not really there.
Frequently asked questions
Do I need to hit my macros exactly?
No. Protein and total calories are the two worth being reasonably tight on — within about 10 g and 100 kcal. Carbs and fat can move around each other freely as long as the calories still land, because the numbers are an estimate built on an estimated metabolic rate in the first place.
Why is protein set at 2 g per kg of bodyweight?
It sits at the top of the range that research consistently shows helps retain muscle while losing fat, and it is easy to remember. Going higher rarely adds anything; going much lower is the most common reason people lose strength on a cut.
Should I eat back the calories I burn in the gym?
No, and this is the most common double-count. Your activity multiplier already includes how often you train. Adding a workout's calories on top counts the same training twice and quietly erases your deficit.
Why do training days and rest days have different targets?
Carbs move to the days you use them. The swing is a redistribution, not an increase: what is added to training days is taken from rest days in proportion, so the weekly average still lands exactly on your target.
How often should I recalculate?
Whenever your bodyweight moves by about 3–4 kg, or when your training frequency changes. Both feed the calculation directly, so a stale weight quietly makes every number slightly wrong.
Do I need to know my body fat percentage?
Not for this method. Mifflin-St Jeor uses only height, weight, age and sex. Formulas that use body fat can be slightly more accurate for very lean people, but they are only as good as your body fat estimate — which for most people is a guess.
Set your height, weight and goal once and the targets follow you into every day's food log.
Open the app