Daily Protein Calculator: How Much Protein Do You Need?

How the calculator works

The logic sits in the page itself. There is no lookup table on a server and no hidden weighting. Your weight in kilograms is multiplied by a low and a high ratio, and the ratios depend on the goal you pick:

The "starting point" is simply the midpoint of the range. That midpoint is our own convenience, not a published figure. Where you land inside a range depends on how hard you train, how much you eat overall, and your preferences. If you are eating in a calorie deficit while lifting, the upper half of your range is a reasonable place to begin, and the ISSN position stand notes that lean, resistance-trained athletes have been studied at higher intakes still during energy restriction.

Where the numbers come from

0.8 g/kg is the RDA. The Recommended Dietary Allowance was set in the National Academies' 2005 Dietary Reference Intakes report. It is the amount that meets the needs of nearly all healthy adults who are not training. The same report gives an acceptable range of 10 to 35 percent of daily calories from protein.

1.4 to 2.0 g/kg is the ISSN range for people who exercise. The International Society of Sports Nutrition position stand on protein and exercise (Jäger et al., 2017) states that 1.4 to 2.0 g of protein per kg of body weight per day is enough for most exercising people to build and maintain muscle mass. It also recommends roughly 0.25 g/kg, or 20 to 40 g, of high-quality protein per serving.

1.6 g/kg is where the gains flatten for most lifters. A meta-analysis of resistance training trials (Morton et al., 2018, British Journal of Sports Medicine) found that protein intake above roughly 1.6 g/kg per day did not add further to the gain in fat-free mass on average. That is why the muscle-building range starts at 1.6 and not 1.4.

A worked example

A person who weighs 70 kg and lifts three times a week picks "Building muscle." The range is 70 × 1.6 = 112 g to 70 × 2.0 = 140 g per day. The midpoint is 126 g, which over four feedings is about 32 g each — inside the 20 to 40 g serving guide.

What a range like this cannot tell you

• Your health status. The ranges are for healthy adults. Kidney disease, pregnancy, a history of disordered eating and some medications all change what is appropriate.
• Older age. Needs and advice can differ for people over 65, so a professional's guidance matters more than a formula here.
• Which weight to use. Published ratios are per kilogram of body weight. Whether current, goal or lean weight is the better basis is a judgment call for someone who knows your situation.
• Protein quality. Animal proteins, soy and most whole-food mixes are simpler to plan around; a narrow plant-only diet may need more attention to variety.

Related calculators

• Macro Calculator — split calories across protein, carbs and fat
• Calorie Calculator — your daily energy target
• Calorie Deficit Calculator — plan a fat-loss timeline

Frequently asked questions

How much protein do I need per day?

The Recommended Dietary Allowance for adults is 0.8 grams of protein per kilogram of body weight per day, which works out to about 56 g for a 70 kg (154 lb) person. The International Society of Sports Nutrition position stand puts the range for people who exercise at 1.4 to 2.0 g/kg per day. This calculator turns your weight and goal into a range using those figures.

Is 0.8 g/kg the right target for someone who works out?

The 0.8 g/kg RDA is set to meet the needs of nearly all healthy, mostly sedentary adults. It is not a performance target. For people who train, the ISSN position stand describes 1.4 to 2.0 g/kg per day as enough to support muscle building and maintenance.

How much protein should I eat per meal?

The ISSN position stand suggests about 0.25 g of high-quality protein per kg of body weight, or an absolute dose of 20 to 40 g, per serving, spread across the day. For a 70 kg person that is roughly 17 to 18 g on the per-kilogram basis, or 20 to 40 g on the absolute basis.

Can you eat too much protein?

For healthy adults, the ISSN position stand describes intakes in the 1.4 to 2.0 g/kg range as safe. People with kidney disease or other medical conditions can have very different limits, so anyone in that group should get an individual target from their doctor or a registered dietitian instead of using a calculator.

Should I use my current weight or my goal weight?

The published ranges are expressed per kilogram of body weight, and this calculator uses the weight you enter. If you carry a lot of extra body fat, a professional can help you decide which weight to base the figure on.

Sources

• Institute of Medicine (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press.
• Jäger R, Kerksick CM, Campbell BI, et al. (2017). International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition, 14:20.
• Morton RW, Murphy KT, McKellar SR, et al. (2018). 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, 52(6):376-384.

This calculator provides general educational information and is not medical advice. Nobody involved in writing it is your doctor. Talk with a doctor or registered dietitian before changing your diet, especially if you have a health condition or take medication.