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Body and nutrition

Protein Calculator

Enter your body weight to see daily protein in grams at three published figures: the adult RDA of 0.8 g per kg, the 1.4 to 2.0 g per kg the International Society of Sports Nutrition gives for people who exercise, and the 1.62 g per kg from a 2018 meta-analysis of resistance training studies. Each is shown per kg and per lb.

Updated · Sources

Weight unit
g/kg

Adds a row for any other figure, for example 1 gram per pound of body weight.

StrengthProtein

ISSN range for people who exercise

112-160 g/day

Adult RDA
64 g
Morton et al.
130 g
Per serving
20 g
Working80 kg × 1.4 = 112 g; 80 kg × 2.0 = 160 g; RDA: 80 kg × 0.8 = 64 g

The headline is 1.4 to 2.0 g per kg of body weight a day, from the International Society of Sports Nutrition. The adult RDA is 0.8 g per kg, the Morton figure 1.62 g per kg, and a serving is 0.25 g per kg.

Estimates like this vary from person to person. If you are under 18, pregnant or have a medical condition, get guidance from a doctor or registered dietitian.

The three sources on one scale

Protein grams a day112 to 160 g

Grams a day for your weight, above each g per kg figure. Lines: the adult RDA at 0.8 and the Morton figure at 1.62. Inner band: the ISSN range. Outer band: the 95% interval around the Morton figure.

Daily protein for your body weight

Sourceg per kgg per lbGrams
Adult RDAUS Dietary Reference Intakes0.800.3664 g
ISSN, low endpeople who exercise1.400.64112 g
ISSN, high endpeople who exercise2.000.91160 g
Morton et al.where gains leveled off1.620.73130 g
Morton et al., uppertop of the 95% interval2.201.00176 g

Grams are per day, for your body weight. ISSN is the International Society of Sports Nutrition. Morton et al. is the 2018 meta-analysis described below.

Protein by body weight

Daily protein in grams for body weights from 100 to 300 lb, at each of the three figures. Find your weight and read across.

WeightRDA
0.8 g/kg		ISSN
1.4-2.0 g/kg		Morton
1.62 g/kg
100 lb45.4 kg36 g64-91 g73 g
110 lb49.9 kg40 g70-100 g81 g
120 lb54.4 kg44 g76-109 g88 g
130 lb59.0 kg47 g83-118 g96 g
140 lb63.5 kg51 g89-127 g103 g
150 lb68.0 kg54 g95-136 g110 g
160 lb72.6 kg58 g102-145 g118 g
170 lb77.1 kg62 g108-154 g125 g
180 lb81.6 kg65 g114-163 g132 g
190 lb86.2 kg69 g121-172 g140 g
200 lb90.7 kg73 g127-181 g147 g
210 lb95.3 kg76 g133-191 g154 g
220 lb99.8 kg80 g140-200 g162 g
230 lb104.3 kg83 g146-209 g169 g
240 lb108.9 kg87 g152-218 g176 g
250 lb113.4 kg91 g159-227 g184 g
260 lb117.9 kg94 g165-236 g191 g
270 lb122.5 kg98 g171-245 g198 g
280 lb127.0 kg102 g178-254 g206 g
290 lb131.5 kg105 g184-263 g213 g
300 lb136.1 kg109 g191-272 g220 g

Grams are rounded to the nearest whole number. The ISSN column is its range of 1.4 to 2.0 g per kg, and the Morton column is the point where gains in fat-free mass leveled off in that analysis.

How it works

Protein figures are usually given in grams per kilogram of body weight per day. This calculator multiplies your weight by three published figures and shows them side by side.

  • The adult RDA: 0.8 g per kg. The Recommended Dietary Allowance in the US Dietary Reference Intakes is 0.80 g of good quality protein per kg of body weight a day for both men and women, set from nitrogen balance studies.
  • ISSN: 1.4 to 2.0 g per kg. The International Society of Sports Nutrition’s 2017 position stand on protein and exercise says an overall daily intake in this range is sufficient for most exercising individuals, for building muscle mass and for maintaining it.
  • Morton et al.: 1.62 g per kg. A 2018 meta-analysis of 49 trials with 1,863 participants found that protein supplementation added to the gains from resistance training, and that beyond a total intake of 1.62 g per kg a day there was no further gain in fat-free mass. The 95% confidence interval ran from 1.03 to 2.20 g per kg.

The headline is the ISSN range because this page sits with the strength calculators. The RDA, the US reference value for adults, is the first row of the table and the first figure under the result.

The formula

Formula
kg          = lb ÷ 2.20462
grams a day = kg × g per kg

g per kg of body weight
adult RDA       0.8 a day
ISSN range      1.4 to 2.0 a day
Morton et al.   1.62 a day
  95% interval  1.03 to 2.20
ISSN serving    0.25 a serving

g per lb = g per kg ÷ 2.20462

Worked example

A person who weighs 180 lb.

  1. Weight in kilograms: 180 ÷ 2.20462 = 81.65 kg.
  2. Adult RDA: 81.65 × 0.8 = 65.3, so 65 g a day.
  3. ISSN range: 81.65 × 1.4 = 114 g and 81.65 × 2.0 = 163 g a day.
  4. Morton et al.: 81.65 × 1.62 = 132 g a day, with the interval running from 84 to 180 g.
  5. Per pound, the ISSN range is 1.4 ÷ 2.20462 = 0.64 to 2.0 ÷ 2.20462 = 0.91 g per lb.

What each source is

  • The RDA is a reference value for healthy adults from the Institute of Medicine’s Dietary Reference Intakes (2005). The same report sets a range for protein as a share of calories, 10 to 35%, and says there were insufficient data to set a Tolerable Upper Intake Level for protein.
  • The ISSN position stand is a society’s review of the research on protein for healthy, exercising individuals. For a single serving it gives a general recommendation of 0.25 g of high-quality protein per kg of body weight, or 20 to 40 g, with servings spread evenly across the day every 3 to 4 hours. It also discusses higher intakes for particular situations. This calculator shows only its general range.
  • Morton and colleagues pooled randomized controlled trials of at least 6 weeks of resistance training with protein supplementation. They wrote that the RDA of 0.8 g per kg appears insufficient for those whose goal is to gain strength and fat-free mass with resistance training.

Limits of these figures

  • All three are per kg of total body weight, which is how the sources state them.
  • The 1.62 g per kg point comes from a two-segment fit to 42 study arms with 723 participants. That fit was not statistically significant (p = 0.079), and the authors present it as a pragmatic estimate with error around it, which is why the interval of 1.03 to 2.20 matters as much as the point.
  • In the same analysis the effect of protein supplementation on fat-free mass was smaller with increasing age and larger in people who were already resistance-trained.
  • The RDA is stated for good quality protein.
  • None of these sources is a prescription for one person, and this page does not turn them into one.

Questions

How much protein do I need a day?

The adult RDA is 0.8 g per kg of body weight, which is 0.36 g per lb: 65 g a day at 180 lb. For people who exercise, the International Society of Sports Nutrition gives 1.4 to 2.0 g per kg, which is 114 to 163 g at the same weight. Enter your own weight above for your figures.

How much protein do I need to build muscle?

Two sources address it directly. The ISSN position stand says 1.4 to 2.0 g per kg a day is sufficient for most exercising individuals for building and maintaining muscle mass. A 2018 meta-analysis of 49 resistance training trials found no further gain in fat-free mass beyond 1.62 g per kg a day, with a 95% confidence interval of 1.03 to 2.20. At 180 lb, 1.62 g per kg is 132 g a day.

Is 1 gram of protein per pound of body weight right?

1 g per lb is 2.20 g per kg. That is the top of the confidence interval in the 2018 meta-analysis by Morton and colleagues, whose best estimate was 1.62 g per kg (0.73 g per lb). The authors wrote that, given the interval, it may be prudent to recommend about 2.2 g per kg for those seeking to maximise gains in fat-free mass from resistance training. The ISSN range tops out at 2.0 g per kg, which is 0.91 g per lb.

How much protein should I eat per meal?

The ISSN position stand gives a general recommendation of 0.25 g of high-quality protein per kg of body weight per serving, or 20 to 40 g, with servings spread evenly across the day every 3 to 4 hours. At 180 lb, 0.25 g per kg is 20 g. The stand describes the research on the best amount per serving as mixed.

Is the RDA enough if I lift weights?

The RDA of 0.8 g per kg is the reference value for adults in general. Morton and colleagues wrote that it appears insufficient for those whose goal is to gain strength and fat-free mass with resistance training, and the ISSN range for exercising individuals starts at 1.4 g per kg.

Is there an upper limit for protein?

The Dietary Reference Intakes did not set a Tolerable Upper Intake Level for protein, because there were insufficient data to do so. They do give an upper end for protein as a share of calories: 35%, the top of the Acceptable Macronutrient Distribution Range. The macro calculator works from that side, turning a share of calories into grams.

How do I convert grams per kg to grams per pound?

Divide by 2.20462, the number of pounds in a kilogram: 0.8 g per kg is 0.36 g per lb, 1.4 g per kg is 0.64 g per lb, 1.62 g per kg is 0.73 g per lb, 2 g per kg is 0.91 g per lb and 2.2 g per kg is 1.00 g per lb.

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Sources

  1. Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press; 2005. Chapter 10, Protein and Amino Acids: summary (page 589).
  2. Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press; 2005. Chapter 11, Macronutrients and Healthful Diets: Acceptable Macronutrient Distribution Ranges (page 769).
  3. Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition. 2017;14:20.
  4. 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. British Journal of Sports Medicine. 2018;52(6):376-384.
  5. National Institute of Standards and Technology. Guide for the Use of the International System of Units (SI), Special Publication 811, Appendix B.9: 1 inch = 2.54 cm and 1 lb = 0.4535924 kg.