Protein calculator: how much protein per day, in grams

The RDA for adults, at 70 kgworked example

56 g

The published range this comes from: 0.8 g/kg/dayIOM Dietary Reference Intakes (2005)
The IOM RDA for this weight, for scale: 56 g
Per meal across 3: 19 gThe ISSN per-meal dose at this weight is 18 g (0.25 g/kg), or an absolute 20–40 g every 3–4 hours

The intake the IOM judged sufficient to meet the requirement of nearly all healthy adults. It is a floor for adequacy, not a figure anyone described as optimal. This is one of four published ranges, and they differ by more than double from end to end — the table below shows all of them in grams for 70 kg, each attributed to the organisation that set it. Which one applies to you is a question about your circumstances, not your arithmetic.

Body weightIn kilograms — every range here is published per kilogram.Meals per dayThe ISSN suggests spreading doses every three to four hours.Daily calories (optional)To express the target as a share of energy against the IOM range.

Which published range?

The RDA for adults 0.8 g/kgIOM Dietary Reference Intakes (2005)Athletes and active adults 1.2–2 g/kgAcademy of Nutrition and Dietetics, Dietitians of Canada and ACSM (2016)Building or maintaining muscle 1.4–2 g/kgInternational Society of Sports Nutrition position stand (2017)Healthy adults over 65 1–1.2 g/kgPROT-AGE Study Group position paper (2013)

All four published ranges, in grams for 70 kg
Range	Per kg	Grams per day	Published by
The RDA for adults	0.8 g/kg	56 g	IOM Dietary Reference Intakes (2005)
Athletes and active adults	1.2–2 g/kg	84–140 g	Academy of Nutrition and Dietetics, Dietitians of Canada and ACSM (2016)
Building or maintaining muscle	1.4–2 g/kg	98–140 g	International Society of Sports Nutrition position stand (2017)
Healthy adults over 65	1–1.2 g/kg	70–84 g	PROT-AGE Study Group position paper (2013)

IOM Dietary Reference Intakes (2005); Academy of Nutrition and Dietetics, Dietitians of Canada and ACSM joint position statement (2016); International Society of Sports Nutrition position stand (2017); PROT-AGE Study Group (2013). PROT-AGE names kidney disease as an exception where intake is a clinical decision.

Protein is one of three shares of a daily calorie figure. To see what these grams leave for carbohydrate and fat inside the IOM ranges, use the macro calculator. For the calorie figure itself, the TDEE calculator estimates it.

Four organisations have published protein ranges: the RDA of 0.8 g per kg from the IOM, 1.2 to 2.0 for athletes in the 2016 ACSM joint statement, 1.4 to 2.0 from the ISSN, and 1.0 to 1.2 for healthy over-65s from PROT-AGE. This shows each of them in grams for your weight.

Protein RDA for adults — 0.8 g protein per kg body weight per day. Verified 2026-07-30 against Institute of Medicine, Dietary Reference Intakes for Macronutrients (2005) (The RDA is the intake judged sufficient to meet the requirement of nearly all healthy adults. It is a floor for adequacy, not an optimum, and the same report's AMDR runs to 35% of energy.)
Protein for athletes and active adults — 1.2 to 2.0 g protein per kg body weight per day. Verified 2026-07-30 against Academy of Nutrition and Dietetics, Dietitians of Canada and ACSM joint position statement (2016) (A range, not a target: the statement notes higher intakes may apply for short periods of intensified training or reduced energy intake.)
Protein for building or maintaining muscle (ISSN) — 1.4 to 2.0 g/kg/day; per meal 0.25 g/kg or an absolute 20-40 g, distributed every 3-4 hours. Verified 2026-07-30 against Jager et al., J Int Soc Sports Nutr 2017 (ISSN position stand) (The stand describes what is sufficient for most exercising individuals, and separately notes 2.3 to 3.1 g/kg/day may apply while in an energy deficit to help preserve lean mass.)
Protein for healthy older adults (PROT-AGE) — at least 1.0 to 1.2 g protein per kg body weight per day for healthy people over 65. Verified 2026-07-30 against Bauer et al., J Am Med Dir Assoc 2013 (PROT-AGE Study Group) (The paper advises 1.2 g/kg/day or more for older people who are exercising or otherwise active, and 1.2 to 1.5 g/kg/day where acute or chronic illness is involved, so the healthy-adult range is a floor rather than a ceiling.)
Acceptable Macronutrient Distribution Ranges (AMDR) — adults: protein 10-35%, carbohydrate 45-65%, fat 20-35% of total energy. Verified 2026-07-30 against Institute of Medicine, Dietary Reference Intakes for Macronutrients (2005) (A range for populations, expressed as a share of energy. The committee set no single optimum inside it, so a split being inside the range is not a score.)

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Frequently asked questions

How much protein do I need per day?

It depends which published range applies to you, and they differ by more than double. The IOM RDA is 0.8 g per kg of body weight, which is 56 g at 70 kg. The sports-nutrition bodies publish 1.2 to 2.0 g per kg for athletes, and PROT-AGE puts healthy older adults at 1.0 to 1.2.

Is the RDA of 0.8 g per kg enough?

It is the amount the IOM judged sufficient to meet the requirement of nearly all healthy adults, which makes it a floor for adequacy rather than an optimum. The same IOM report allows protein up to 35 percent of total energy, and later position statements from sports-nutrition bodies sit well above the RDA.

How much protein per meal?

The ISSN position stand puts a per-meal dose at 0.25 g per kg of body weight, or an absolute 20 to 40 g, ideally spread every three to four hours. This tool shows your daily range divided by your number of meals alongside that published dose, so you can see whether the two agree.

Do older adults need more protein?

The PROT-AGE Study Group recommends at least 1.0 to 1.2 g per kg per day for healthy people over 65, more than the 0.8 RDA, and 1.2 or above for those who are active. Their paper names kidney disease as the exception, where intake is a clinical decision rather than a calculator one.

Can I use my goal weight instead of my current weight?

The ranges were published against body weight as measured, so that is what this tool uses. Entering a different figure produces the target for a different body, which is a legitimate thing to look at as long as you know that is what you are looking at.

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The next number

No body metric means much on its own. Here is what this one feeds into.

Macro calculatorProtein is one of three shares of a calorie figure. See what your grams leave for carbohydrate and fat inside the IOM ranges.TDEE calculatorTo express this target as a share of energy you need a calorie figure, and that is what the TDEE page estimates.

Related calculators

Macro calculatorNutrition targets TDEE calculatorMetabolism Water intake calculatorNutrition targets

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