# How much protein for muscle gain?

Estimates grams of protein a day for building muscle with resistance training, from body weight and a sourced range of 1.6 to 2.2 grams per kilogram.

- Page: https://www.acalculator.org/health/protein-for-muscle-gain-calculator
- JSON spec: https://www.acalculator.org/health/protein-for-muscle-gain-calculator.json
- Version: 7343b412ef8c

## Default answer

Example with the default inputs (Weight 180 lb): For muscle gain, aim for about 155 g of protein a day, in a range of 131 g to 180 g.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| weight | Weight | Your body weight. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| protein | Protein a day | Grams of protein a day: body weight × 1.9 g/kg, the middle of the range. |
| low | Range from | The low end of the range: body weight × 1.6 g/kg. |
| high | Range up to | The high end of the range: body weight × 2.2 g/kg. |
| calories | Calories from this protein | Calories a day from the protein: grams × 4. |

## Method

Protein a day (g) = body weight (kg) × 1.9, the middle of a range of 1.6 to 2.2 g per kg.

## Assumptions

- The range is 1.6 to 2.2 g per kg of body weight a day (0.73 to 1.00 g per lb), for adults doing resistance training.
- Weight is total body weight. For people with a lot of body fat, a dietitian may use a lower reference weight.
- Protein gives 4 calories per gram.
- This is an estimate for planning, not medical advice.

## Worked examples

1. weight = 81.646627 gives protein = 0, low = 0, high = 0, calories = 621. Source: Morton RW, Murphy KT, McKellar SR, et al. Br J Sports Med 2018;52(6):376-384 (gains in fat-free mass plateau at 1.62 g/kg a day, 95% CI 1.03 to 2.20), https://pmc.ncbi.nlm.nih.gov/articles/PMC5867436/ (retrieved 2026-11-01).
2. weight = 70 gives protein = 0, low = 0, high = 0, calories = 532. Source: Morton RW, Murphy KT, McKellar SR, et al. Br J Sports Med 2018;52(6):376-384 (gains in fat-free mass plateau at 1.62 g/kg a day, 95% CI 1.03 to 2.20), https://pmc.ncbi.nlm.nih.gov/articles/PMC5867436/ (retrieved 2026-11-01).
3. weight = 90.718474 gives protein = 0, low = 0, high = 0, calories = 689. Source: Morton RW, Murphy KT, McKellar SR, et al. Br J Sports Med 2018;52(6):376-384 (gains in fat-free mass plateau at 1.62 g/kg a day, 95% CI 1.03 to 2.20), https://pmc.ncbi.nlm.nih.gov/articles/PMC5867436/ (retrieved 2026-11-01).

## FAQ

### How much protein do I need for muscle gain?

This page uses 1.6 to 2.2 grams per kilogram of body weight a day, which is 0.73 to 1.00 grams per pound. At 180 lb that is about 131 to 180 grams a day, with 155 grams as the middle of the range.

### Where does the range come from?

A 2018 review and meta-analysis by Morton and colleagues pooled resistance training studies. Gains in fat-free mass stopped rising at about 1.62 g/kg a day, and the upper end of the 95% confidence interval was 2.20 g/kg a day.

### Is more protein better?

In that review, protein beyond about 1.62 g/kg a day gave no further gains in fat-free mass. The authors note that this break point was not statistically significant, so it is an estimate. The upper figure allows for that uncertainty.

### Do I need to lift weights for this to apply?

Yes. The studies behind the range looked at protein alongside resistance training. Protein on its own does not build muscle.

### How many calories is this protein?

Protein gives 4 calories per gram, so 155 grams is about 620 calories a day. Count it as part of your daily calories, not on top of them.

### Should I check with a doctor?

If you have kidney disease, are pregnant, or follow a medical diet, ask your doctor or a dietitian first. This page is an estimate for planning, not medical advice.

## Sources

- Morton RW, Murphy KT, McKellar SR, 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 in healthy adults. Br J Sports Med. 2018;52(6):376-384 (break point 1.62 g/kg a day, 95% CI 1.03 to 2.20, p = 0.079). Retrieved 2026-11-01. https://pmc.ncbi.nlm.nih.gov/articles/PMC5867436/
- U.S. Code of Federal Regulations, 21 CFR 101.9(c)(1)(i)(B): general factors of 4 calories per gram of protein (Cornell LII copy). Retrieved 2026-11-01. https://www.law.cornell.edu/cfr/text/21/101.9
- NIST Guide to the SI (SP 811), Appendix B.8: the inch is exactly 0.0254 m; the avoirdupois pound is 0.4535924 kg to seven figures. Retrieved 2026-11-01. https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8