# How much protein do I need a day?

Estimates grams of protein a day from body weight and a sourced range per kilogram: the adult RDA, older adults, pregnancy, breastfeeding, regular exercise, or building muscle.

- Page: https://www.acalculator.org/health/protein-calculator
- JSON spec: https://www.acalculator.org/health/protein-calculator.json
- Version: 29a2e547419e

## Default answer

Example with the default inputs (Weight 150 lb, Who is it for? Most adults (RDA): 0.8 g/kg): Aim for about 54 g of protein a day (0.8 g per kg of body weight, or 0.36 g per lb).

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| weight | Weight | Your body weight. |
| goal | Who is it for? | The group or goal, which sets the grams of protein per kilogram of body weight. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| protein | Protein a day | Grams of protein a day: body weight × the middle of the range for the goal. |
| low | Range from | The low end of the range: body weight × the lower grams per kilogram. |
| high | Range up to | The high end of the range: body weight × the higher grams per kilogram. |
| rate | Per kilogram | The grams per kilogram (and per pound) used. |
| calories | Calories from this protein | Calories a day from the protein: grams × 4. |

## Method

Protein a day (g) = body weight (kg) × grams per kilogram for the goal; ranges use their middle value.

## Assumptions

- Grams per kilogram a day: most adults 0.8 (RDA); 65 and older 1.0 to 1.2; pregnant 1.1; breastfeeding 1.3; regular exercise 1.4 to 2.0; building muscle 1.6 to 2.2.
- The daily figure is the middle of the range; the low and high ends are shown too.
- 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 = 68.038856, goal = rda gives protein = 0.054431, rate = 0.8 g per kg of body weight, or 0.36 g per lb, calories = 217.724338. Source: IOM 2005 protein RDA, 0.8 g/kg a day; hand calculation in content.mdx.
2. weight = 70, goal = active gives protein = 0.119, low = 0.098, high = 0.14, calories = 476. Source: ISSN position stand (Jäger et al. 2017), 1.4 to 2.0 g/kg a day; hand calculation in content.mdx.
3. weight = 80, goal = older gives protein = 0.088, low = 0.08, high = 0.096. Source: PROT-AGE Study Group (Bauer et al. 2013), 1.0 to 1.2 g/kg a day; hand calculation in content.mdx.
4. weight = 65, goal = pregnant gives protein = 0.0715, rate = 1.1 g per kg of body weight, or 0.50 g per lb. Source: IOM 2005 protein RDA in pregnancy, 1.1 g/kg a day; hand calculation in content.mdx.
5. weight = 90.718474, goal = muscle gives protein = 0.172365, low = 0.14515, high = 0.199581. Source: Morton et al. 2018 (gains plateau at 1.62 g/kg, 95% CI up to 2.20); hand calculation in content.mdx.

## FAQ

### How much protein do I need a day?

The Recommended Dietary Allowance (RDA) for adults is 0.8 grams of protein per kilogram of body weight a day, or about 0.36 grams per pound. At 150 lb (68 kg), that is about 54 grams a day. The RDA is set to cover the needs of nearly all healthy adults.

### How much protein do I need if I exercise?

The International Society of Sports Nutrition (2017) says 1.4 to 2.0 grams per kilogram a day is enough for most people who exercise. At 70 kg that is 98 to 140 grams, and the calculator shows the middle, 119 grams.

### How much protein do I need to build muscle?

A 2018 meta-analysis of weight-training trials found that muscle gains from weight training stopped rising above about 1.6 grams per kilogram a day, with an upper estimate of 2.2. The calculator uses 1.6 to 2.2 grams per kilogram for this goal.

### Do older adults need more protein?

The PROT-AGE Study Group (2013) recommends 1.0 to 1.2 grams per kilogram a day for healthy people aged 65 and older, more than the adult RDA, to help keep muscle and strength. People with some illnesses may need more, and people with severe kidney disease may need less, so ask a doctor.

### How much protein do I need when pregnant or breastfeeding?

The National Academies set the RDA at 1.1 grams per kilogram a day during pregnancy (for the second half) and 1.3 grams per kilogram a day while breastfeeding.

### Can I eat too much protein?

For healthy adults, the National Academies set no upper limit for protein, and its acceptable range goes up to 35% of calories. People with kidney disease should follow their doctor's advice on protein.

## Sources

- Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press; 2005 (protein RDA 0.8 g/kg a day for adults, 1.1 in pregnancy, 1.3 in lactation). https://www.nationalacademies.org/publications/10490
- Bauer J, Biolo G, Cederholm T, et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. J Am Med Dir Assoc. 2013;14(8):542-559. https://doi.org/10.1016/j.jamda.2013.05.021
- Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20. https://doi.org/10.1186/s12970-017-0177-8
- 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. https://doi.org/10.1136/bjsports-2017-097608
- U.S. Code of Federal Regulations, 21 CFR 101.9(c)(1)(i)(C): 4 calories per gram of protein. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-101/subpart-A/section-101.9