How much protein per day to build muscle

You’re lifting, and you want to know how much protein it takes to build muscle. For healthy adults who train, research points to about 1.6 g of protein per kilogram of body weight a day (about 0.73 g per pound). Going up to about 2.2 g/kg (1 g per pound) may help if you want to get the most out of training.

You may have seen a much lower number, 0.8 g/kg (0.36 g per pound). That’s the adult RDA. It covers the basic needs of nearly all healthy adults, and it isn’t a target for building muscle.

This post is for generally healthy adults and isn’t medical advice. If you have a medical condition, are pregnant, or have a history of an eating disorder, talk with a doctor or registered dietitian before you change how much protein you eat.

Where 1.6 comes from

A 2018 review pooled 49 trials with 1,863 healthy adults. Each trial put people on resistance training for at least six weeks and compared a group taking protein supplements with a group that trained without them. Gains in fat-free mass leveled off at about 1.6 g/kg a day.

That estimate is loose, and it came from a subset of the trials. The likely range ran from about 1.0 to 2.2 g/kg (0.45 to 1 g per pound). So the authors suggested aiming near 2.2 g/kg if you want every bit of gain. That’s a cautious upper target. It isn’t a safety limit, and it doesn’t prove that everyone gains more at 2.2 than at 1.6.

The International Society of Sports Nutrition lands in a similar place. Its 2017 position stand says 1.4 to 2.0 g/kg (0.64 to 0.91 g per pound) a day suits most people who exercise. People who lift while eating fewer calories than they burn may need 2.3 to 3.1 g/kg (1.04 to 1.41 g per pound) to keep their muscle.

Daily protein per kg of body weight

Adult RDA 0.8 g/kg (0.36 g/lb). Meets the needs of nearly all healthy adults. Not a muscle-building target.
Morton et al. 2018, where gains leveled off About 1.0 to 2.2 g/kg (0.45 to 1 g/lb). Fat-free mass gains leveled off near 1.6. The bar is the uncertainty around that point, not a target range.
ISSN, most people who exercise 1.4 to 2.0 g/kg (0.64 to 0.91 g/lb).
ISSN, lifting while eating less 2.3 to 3.1 g/kg (1.04 to 1.41 g/lb). May be needed to keep muscle.

Dashed lines mark the two targets in this post, 1.6 and 2.2 g/kg. The diamond marks where fat-free mass gains leveled off in the 2018 review, and its bar shows how uncertain that point is. The RDA is half of 1.6.

Find your daily grams

Multiply your weight in kilograms by 1.6. Use 2.2 instead if you’re aiming high.

Protein a day, 1.6 to 2.2 g/kg

Daily protein at 1.6 and 2.2 g per kg for body weights from 120 to 240 lb
Body weight in lb	Body weight in kg	Protein a day at 1.6 g/kg	Protein a day at 2.2 g/kg
120	54	87 g	120 g
140	64	102 g	140 g
160	73	116 g	160 g
180	82	131 g	180 g
200	91	145 g	200 g
220	100	160 g	220 g
240	109	174 g	239 g

These are daily totals, not amounts for one meal. Kilograms are rounded, but grams use the exact weight, so shortcuts like rounded kilograms times 1.6 or 2.2, or pounds times 0.73 or 1, can be off by 1 g.

If you weigh yourself in pounds, multiply your weight by 0.73 for 1.6 g/kg, or by 1 for 2.2 g/kg. Don’t use the per-kilogram numbers with your weight in pounds. That more than doubles the result.

Pounds take 0.73, not 1.6

Right 180 lb × 0.73 = 131 g

Mistake 180 lb × 1.6 = 288 g

180 lb is 81.6 kg, and 81.6 × 1.6 also gives 131 g. The 1.6 is per kilogram, so using it with pounds gives 288 g, more than double.

Spread it through the day

The same position stand suggests about 0.25 g/kg (0.11 g per pound) in each meal, or 20 to 40 g, every 3 to 4 hours.

Take an 80 kg (176 lb) lifter aiming for 1.6 g/kg. That’s 128 g a day. Four meals with 32 g each get there, and each meal lands inside the 20 to 40 g range.

128 g a day in 4 meals

ISSN suggests 20 to 40 g a meal, every 3 to 4 hours

32 g Meal 1
32 g Meal 2
32 g Meal 3
32 g Meal 4

An 80 kg (176 lb) lifter at 1.6 g/kg: 4 × 32 g = 128 g. Each meal lands inside the 20 to 40 g range.

How it fits your calories

Each gram of protein has about 4 calories, so 128 g is 512 calories. In a 2,500-calorie day, that’s about 20% of your calories. The National Academies put the adult range for protein at 10% to 35% of calories, so that fits. These numbers are a math example, not a meal plan.

Set your protein goal in grams

Once you have your number, put it straight into your goals. Recalculate Targets in MACROS sets protein as a share of calories, using the presets in the macro goals guide. To use a g/kg target, type the grams in yourself.

Open Settings and find Daily Goals.
Type your grams into Protein. Then adjust Calories, Carbs, or Fat so the four numbers fit together, because changing Protein doesn’t change your calorie goal.
Tap Save Goals.

MACROS Settings with editable Daily Goals and Recalculate Targets. — Settings > Daily Goals. These demo values show the controls, not the worked example or a recommended diet.

Sources

The National Academies DRI summary tables, protein footnote b, give the adult RDA of 0.8 g/kg and define the RDA.
Morton et al. 2018, in the PubMed abstract and full text, is the review of 49 trials. Stuart Phillips disclosed support from the US National Dairy Council. A 2020 correction added Brad Schoenfeld’s advisory-board role with Dymatize Nutrition.
Jäger et al. 2017, the ISSN position stand, gives the daily ranges and the per-meal amounts.
The National Academies AMDR report, Table 3-1, gives the adult protein range of 10% to 35% of calories.
21 CFR 101.9(c)(1)(i)(B) gives the general factor of 4 calories per gram of protein.

Sources checked November 7, 2026, using the eCFR as amended through November 5, 2026. App steps checked the same day. This post is general information, not medical advice, and no dietitian or doctor reviewed it.