Protein calculator: how much protein do you need a day?

For healthy, mostly inactive adults, the US National Academies (formerly IOM) set the RDA at 0.8 g of protein per kilogram of body weight a day, or about 0.36 g per pound. That's the amount that prevents deficiency in nearly everyone, not the best amount for everyone.

Needs go up with regular training, older age or weight loss. The calculator uses these ranges:

Daily protein = body weight × the g/kg value for your goal, shown as a range when the guideline gives one. We then divide it by your number of meals so you can see how much to aim for at each.

If you have obesity (BMI 30 or more), using your full weight would overstate your needs, because fat tissue needs little protein. In that case the calculator uses the weight that matches a BMI of 25 (a reference weight), or your goal weight if you enter one. The result tells you when this applies.

The ISSN position stand says about 0.25–0.4 g/kg per meal (roughly 20 to 40 g for most adults) best supports muscle protein synthesis, so it helps to spread your protein over 3 to 5 meals.

An adult who weighs 154 lb (70 kg), is 5 ft 9 in (175 cm) tall, works out three times a week and eats four meals a day.

• BMI: 22.9, so we use full body weight.
• Daily protein: 70 × 1.2–1.6 = 84–112 g
• Per meal: 84–112 ÷ 4 = 21–28 g

For someone building muscle at 243 lb (110 kg) and 5 ft 9 in (BMI 35.9), the calculator uses a reference weight of about 169 lb (76.6 kg): 76.6 × 1.6–2.2 = 123–168 g a day. Using full body weight would give 176–242 g, which is more than needed.

Some typical values per 100 g (about 3.5 oz); check labels for exact numbers:

So 25 g of protein is roughly 3 oz of chicken breast, a cup of cottage cheese or 4 eggs. On a plant-based diet, mixing beans, lentils, tofu and grains gives you all the essential amino acids. You can look up more foods in our calorie chart.

• Kidney disease: with chronic kidney disease, your doctor or dietitian sets your protein intake, often lower than usual. Don't use this calculator in that case.
• Pregnancy and breastfeeding: from the second half of pregnancy and while breastfeeding, the IOM recommends about 1.1 g/kg, or roughly 25 g more a day. Ask your midwife, OB or a dietitian.
• Children and teens: needs change with age, and adult values don't apply.
• Very high intakes: for healthy adults, going above 2.2 g/kg a day hasn't been shown to add muscle. Protein powders are convenient, but food can cover your needs.

Protein is only one part of the picture. During weight loss, a higher intake (1.6–2.2 g/kg) helps you keep muscle, but you also need strength training and a moderate calorie deficit. If you don't know your daily energy needs yet, start with the calorie calculator, plan weight loss with the calorie deficit calculator and set your protein, carb and fat split in the macro calculator.

For older adults, regular muscle-strengthening activity matters as much as protein for keeping muscle. The PROT-AGE group recommends 1.0–1.2 g/kg a day over 65, and more than 1.2 g/kg for those who are active.