How much protein do I need to build muscle?

1.8 g per kg of body weight per day — 126 g for a 70 kg lifter, 162 g at 90 kg. Meta-analysis puts the useful ceiling for muscle gain near 1.6 g/kg; the extra is margin for days you miss.

Should protein go up when cutting?

Yes. Month6 uses 2.2 g/kg in a deficit, where protein does the most to hold on to muscle while fat comes off, against 1.8 g/kg when building.

Is more protein better?

Not past the range the evidence supports. The ISSN position stand gives 1.4–2.0 g/kg for people doing resistance training, more while in a deficit; beyond that the return is small and the calories displace food you need.

Is this medical advice?

No. These are targets for healthy adults doing resistance training. If you have kidney disease or any condition that affects protein intake, ask your doctor first.

Guides

How much protein per day?

Short answer

1.8 g per kilogram of body weight a day to build muscle, 2 g/kg to recomp, and 2.2 g/kg while cutting — so an 80 kg lifter eats 144 g building and 176 g in a deficit, where protein does the most to protect muscle.

Numbers computed from the Month6 engine; last checked 5 October 2026.

The number for your body weight

Daily protein target by body weight and goal
Body weight	Build	Recomp	Cut
50 kg	90 g	100 g	110 g
60 kg	108 g	120 g	132 g
70 kg	126 g	140 g	154 g
80 kg	144 g	160 g	176 g
90 kg	162 g	180 g	198 g
100 kg	180 g	200 g	220 g

Why it depends on the goal

Building muscle needs enough protein to turn a surplus into tissue rather than fat; meta-analysis of resistance-training studies finds the benefit plateaus near 1.6 g/kg, so 1.8 g/kg is that figure with margin. In a deficit the job changes: protein is what stops the body taking the shortfall out of muscle, and the evidence for natural lifters cutting supports going higher — hence 2.2 g/kg. A recomp sits between, at 2 g/kg, because it is doing both at once.

What about calories?

Protein is the anchor; calories are the dial. The calorie target comes from your resting energy and training frequency, scaled by the goal — the calorie calculator runs it for your numbers, with a deficit floor the engine will not cross.

Questions

An estimate for healthy adults, not medical advice. How every number is made, with its citations: Sources & method.

Your own numbers

Calorie & protein calculator — free, in your browser, nothing sent anywhere.

See your six-month body. Then go earn it.

Month6sets this target from the same formula as your six-month curve, shows it as the day's protein ring, and lets you log a meal by photo, by text or from a food library in one tap.