How to calculate your macros for bulking, cutting, or recomp

Start with maintenance calories

Everything downstream depends on one number: the calories you burn in a typical day, often called TDEE (total daily energy expenditure). You can't measure it at home, but you can estimate it well enough to start, then correct it from real results.

The most widely used estimate begins with the Mifflin-St Jeor equation for resting metabolism (BMR), using weight in kilograms, height in centimetres, and age in years:

• Men: 10 × weight + 6.25 × height − 5 × age + 5
• Women: 10 × weight + 6.25 × height − 5 × age − 161

Then multiply BMR by an activity factor to account for daily movement and training:

• 1.2 — desk job, little deliberate exercise
• 1.375 — light training 1–3 days a week
• 1.55 — moderate training 3–5 days a week
• 1.725 — hard training 6–7 days a week
• 1.9 — hard training plus a physically demanding job

Worked example. A 28-year-old man, 80 kg, 180 cm, lifting four days a week. BMR = 10 × 80 + 6.25 × 180 − 5 × 28 + 5 = 1,790 kcal. At a 1.55 activity factor, maintenance ≈ 1,790 × 1.55 ≈ 2,775 kcal.

The single most common mistake is picking too high an activity factor. Four hour-long lifting sessions a week feel like a lot, but a lifting session burns far less than people expect, and the other 164 hours of the week are usually sedentary. If you sit for work and train four times a week, 1.5–1.55 is a more honest starting point than 1.7. You'll correct it later either way.

Pick the goal, then the pace

Your goal sets which direction calories move from maintenance; your pace sets how far. Faster is not better — a bigger surplus adds more fat per unit of muscle, and a bigger deficit costs more muscle and more adherence.

Bulking (gain muscle)

Add roughly 10–20% above maintenance, typically 250–500 kcal. Aim to gain about 0.25–0.5% of bodyweight per week — for an 80 kg lifter, that's 200–400 g a week. Newer lifters can sit at the top of that range; experienced lifters gain muscle more slowly and should stay near the bottom to avoid spending a bulk mostly on fat.

Cutting (lose fat)

Subtract roughly 10–25% below maintenance, typically 300–700 kcal. Aim to lose about 0.5–1% of bodyweight per week. The leaner you already are, the slower you should go: a 20% deficit is reasonable at higher body fat, while someone already lean holds more muscle at 10–15%.

Recomp (build muscle and lose fat at the same time)

Eat at or very near maintenance — within about 5% either side — with protein at the high end of the range below, and let training drive the change. Recomp works best for beginners, people returning after a layoff, and anyone carrying enough body fat to fuel muscle growth from stored energy. Expect the scale to move slowly or not at all; progress shows up in the mirror, in measurements, and in lifts, not in weight.

Continuing the example. Maintenance is 2,775 kcal. A moderate bulk: 2,775 + 300 = 3,075 kcal. A moderate cut: 2,775 − 500 = 2,275 kcal. A recomp: ≈ 2,775 kcal.

Set protein first

Protein is the macro that most directly protects and builds muscle, so it gets set first and everything else fits around it. Anchor it to bodyweight, not a percentage of calories — a percentage swings with your calorie target while your body's need doesn't.

• Bulking or recomp: 1.6–2.2 g per kg of bodyweight. For most lifters, benefits flatten above about 1.6 g/kg; 2.0–2.2 gives useful margin.
• Cutting: 2.2–2.6 g per kg, or higher. A deficit is when muscle is most at risk, and protein is also the most filling macro — both reasons to push it up.
• If you carry a lot of body fat: base the number on your estimated lean mass or a realistic goal weight, not total weight, or the target inflates.

Protein has 4 kcal per gram, so multiply grams by four to see how many of your calories it takes. Our guide on how much protein you need to build muscle goes deeper on timing, distribution, and sources.

Example. 80 kg, bulking at 2.0 g/kg: 160 g protein = 640 kcal. Cutting at 2.4 g/kg: 192 g protein = 768 kcal.

Set fat second

Fat supports hormone production, joint health, and the absorption of several vitamins, so it has a floor. Set it at 0.6–1.0 g per kg of bodyweight — about 20–35% of total calories for most people — and don't hold it below roughly 0.5 g/kg for long, especially on a cut, where it's tempting to squeeze fat to make room for carbs.

Fat has 9 kcal per gram, more than double protein or carbs, which is why small amounts of oil, butter, and dressing move calorie totals so much — and why they're the ingredients most often missed when tracking.

Example. 80 kg, bulking at 0.8 g/kg: 64 g fat = 576 kcal. Cutting at 0.7 g/kg: 56 g fat = 504 kcal.

Carbs fill the rest

Whatever calories remain after protein and fat go to carbohydrates, which at 4 kcal per gram are the main fuel for hard training. There's no need to fear a high carb number on a bulk; it's what powers the sessions that turn a surplus into muscle rather than fat.

Carbs (g) = (total calories − protein calories − fat calories) ÷ 4

Bulk, 3,075 kcal: (3,075 − 640 − 576) ÷ 4 ≈ 465 g carbs. Final targets: 160 g protein · 64 g fat · 465 g carbs.

Cut, 2,275 kcal: (2,275 − 768 − 504) ÷ 4 ≈ 250 g carbs. Final targets: 192 g protein · 56 g fat · 250 g carbs.

If the carb number comes out uncomfortably low on a cut — under roughly 100 g — the deficit is probably too aggressive, or fat is set higher than it needs to be. Take a smaller deficit rather than cutting protein.

Adjust from the trend, not the day

The estimate above is a starting point, and it will be off — every formula is. What makes the method work is the correction loop. Weigh yourself in the same conditions each morning, ignore the daily number, and compare weekly averages every two weeks:

1. Bulking and gaining faster than 0.5%/week? Subtract 100–200 kcal, mostly from carbs. Slower than 0.25%/week or not at all? Add 100–200 kcal.
2. Cutting and losing faster than 1%/week? Add 100–200 kcal. Slower than 0.5%/week? Subtract 100–200 kcal — but confirm your logging first (see below).
3. Recomp? Judge by measurements, photos, and lifts over 6–8 weeks, not by the scale.
4. Every 5 kg of weight change, re-run the numbers. Maintenance moves with your bodyweight.

Daily weight swings by a kilogram or more with water, glycogen, sodium, and what's still in your digestive system. Reacting to a single day's reading is how people ping-pong their calories and conclude the method doesn't work. The two-week weekly-average comparison filters that noise.

One more honest note: if the scale isn't moving on a cut, the most likely explanation is under-logging, not a broken metabolism. Oils, sauces, bites while cooking, and untracked weekends add up. Our guide on how accurate AI calorie tracking really is covers where logging errors come from and how to shrink them.

Common mistakes

• Choosing an activity factor by how hard training feels rather than how much you move in total. Start lower; the trend will tell you.
• Setting protein as a percentage. Anchor it to bodyweight so it doesn't drop when calories do.
• Cutting fat too low to fit more carbs. Hold the 0.5 g/kg floor.
• Adjusting off daily weight. Use two-week comparisons of weekly averages.
• Never re-calculating. A target set at 90 kg is wrong at 80 kg.
• Trusting the numbers more than the outcome. The formula gets you close; results get you the rest of the way.

How GainzMate does this

This is the same method GainzMate is being built to run during onboarding. You enter age, height, weight, activity, training frequency, goal, and preferred pace; the app returns calorie and macro targets using deterministic calculations — the same inputs always produce the same targets, with no black box and no AI in the loop. Every target stays editable, so if you'd rather run your own numbers from this guide, you can type them straight in.

GainzMate is currently in development for iPhone. See what's planned or read the FAQ for where things stand.