Protein calculator: how much protein do you need per day?
This protein calculator turns your body weight into a daily protein intake in grams using the ranges its sources actually publish: the National Academies' RDA of 0.8 g per kg, the ISSN's 1.4–2.0 g per kg for people who exercise (2.3–3.1 in a calorie deficit) and PROT-AGE's 1.0–1.2 g per kg after 65. It splits the result across 3, 4 or 5 meals and, if you enter your calories, shows protein as a share of them. Free, no sign-up, and nothing you type is stored.
How much protein do I need a day? Multiply your body weight in kilograms by the figure for your situation: 0.8 g for the adult RDA (National Academies), 56 g at 70 kg; 1.4–2.0 g if you exercise to build or keep muscle (ISSN), 98–140 g; 1.0–1.2 g for a healthy adult over 65 (PROT-AGE), 70–84 g.
| Meals a day | Low end | Midpoint | High end |
|---|---|---|---|
| 3 meals | — | — | — |
| 4 meals | — | — | — |
| 5 meals | — | — | — |
For comparison, the ISSN's per-serving guidance is 0.25 g of high-quality protein per kg of body weight, — at your weight, or an absolute 20–40 g, spaced every 3–4 hours.
| Food (FDC ID) | Protein per 100 g | Amount for 30 g | Calories in that amount |
|---|---|---|---|
| Chicken breast, roasted, meat only (171477) | 31.0 g | 97 g, a little over half a breast | 160 kcal |
| Tuna, light, canned in water, drained (173709) | 19.4 g | 155 g, just under one 165 g can | 133 kcal |
| Cottage cheese, 1 % milkfat (173417) | 12.4 g | 242 g, about 1 cup | 174 kcal |
| Tofu, firm (172475) | 17.3 g | 173 g, about ⅔ cup | 250 kcal |
| Salmon, Atlantic, farmed, cooked (175168) | 22.1 g | 136 g, just under 5 oz | 280 kcal |
| Lentils, cooked (172421) | 9.0 g | 333 g, about 1⅔ cups | 386 kcal |
| Greek yogurt, plain, nonfat (170894) | 10.2 g | 294 g, about 1¾ containers of 170 g | 174 kcal |
| Whey protein isolate (173177) | 58.1 g | 52 g, almost 2 scoops | 185 kcal |
| Black beans, cooked (173735) | 8.9 g | 339 g, about 2 cups | 447 kcal |
| Milk, nonfat (171269) | 3.4 g | 890 g, about 3½ cups | 303 kcal |
| Egg, hard-boiled (173424) | 12.6 g | 238 g, almost 5 large eggs | 369 kcal |
Amounts are 30 ÷ protein per 100 g × 100; calories are that amount × the record's kcal per 100 g. Cup and can equivalents use USDA's own portion weights for each record.
Values recalculate instantly as you type. Nothing is sent or stored — the math runs in your browser.
How the calculation works
The calculator multiplies your body weight in kilograms by the grams-per-kilogram range that the source for your situation states, reports both ends and their midpoint, and divides the result by 3, 4 or 5 for the per-meal figures. Nothing else goes in: every source multiplies body weight, and none of the passages quoted below adjusts for body composition, so the calculator does not either.
Daily protein = body weight (kg) × g/kg, at both ends of the range; midpoint = (low + high) ÷ 2. In pounds, g/lb = g/kg ÷ 2.20462.
General adult: 0.8 g/kg, the RDA. The National Academies' table footnote: "for adults 0.8 g/kg body weight for the reference body weight". 56 g at 70 kg.
Exercising, building or keeping muscle: 1.4–2.0 g/kg. ISSN position stand: "an overall daily protein intake in the range of 1.4–2.0 g protein/kg body weight/day (g/kg/d) is sufficient for most exercising individuals". 98–140 g at 70 kg.
Resistance-trained, in a calorie deficit: 2.3–3.1 g/kg. ISSN: "Higher protein intakes (2.3–3.1 g/kg/d) may be needed to maximize the retention of lean body mass in resistance-trained subjects during hypocaloric periods." 161–217 g at 70 kg.
Healthy adult over 65: 1.0–1.2 g/kg. PROT-AGE: "average daily intake at least in the range of 1.0 to 1.2 g protein per kilogram of body weight per day", and 1.2 g/kg or more "for those who are exercising and otherwise active". 70–84 g at 70 kg.
Per meal = daily grams ÷ meals. The ISSN's own serving guidance: "0.25 g of a high-quality protein per kg of body weight, or an absolute dose of 20–40 g", "evenly distributed, every 3–4 h, across the day".
Share of calories = grams × 4 kcal per gram ÷ your daily calories. The Dietary Reference Intakes' Acceptable Macronutrient Distribution Range for protein is 10–35 % of energy.
Sources: National Academies of Sciences, Engineering, and Medicine, Dietary Reference Intakes: Recommended Dietary Allowances and Adequate Intakes, Total Water and Macronutrients (the RDA table) and Dietary Reference Intakes: Acceptable Macronutrient Distribution Ranges, both via NCBI Bookshelf. 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 (doi:10.1186/s12970-017-0177-8; open access). 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, Journal of the American Medical Directors Association, 2013;14(8):542–559 (doi:10.1016/j.jamda.2013.05.021). The 4 kcal per gram of protein is the factor nutrition labels use, as what is a calorie explains. Food data: USDA FoodData Central, SR Legacy (2019), records 171477, 173709, 173417, 172475, 175168, 172421, 170894, 173177, 173735, 171269 and 173424; the per-100 g values are USDA's, and the amounts for 30 g and their calories are arithmetic on those records. The same ranges, multiplied out for 50 to 110 kg, are tabulated in how many grams of protein a day.
Limits of the estimate
All three sources multiply body weight, and none of the passages quoted adjusts for body composition, so the calculator does not either; a registered dietitian can adjust the multiplier, a web page cannot. The ranges are for healthy adults. PROT-AGE states that most older adults with acute or chronic disease need 1.2–1.5 g/kg, a range for a clinician rather than an option here. None of the sources publishes a weight-loss multiplier for people who are not resistance-trained, so the calculator does not invent one. The result is not a reference during pregnancy or breastfeeding, under 18, or with kidney or liver disease; in those cases the number should come from a healthcare professional. And if counting grams of protein makes eating feel stressful rather than clearer, that is a reason to stop counting and talk to someone, not to count more carefully.
Frequently asked questions
How do I calculate protein content in food?
Grams of protein per 100 g × portion weight ÷ 100, using the label or USDA FoodData Central: roasted chicken breast is 31.0 g per 100 g, so USDA's 86 g half breast is 26.7 g (FDC 171477). Without a scale, PlateLens estimates the protein from a photo, a plain-words description or a barcode, and "Fix it" corrects the portion in one sentence.
Is eating 100 g of protein a day enough?
It depends on your weight and situation. 100 g covers the 0.8 g/kg RDA for anyone up to 125 kg. For someone exercising to build or keep muscle, the ISSN's 1.4–2.0 g/kg makes 100 g enough between 50 and 71 kg and short of the low end above that: an 80 kg person needs 112–160 g.
How much protein do you need to lose weight?
Of the three sources this calculator uses, only the ISSN gives a figure for a calorie deficit, and only for resistance-trained people: 2.3–3.1 g/kg to retain lean mass, 161–217 g at 70 kg. None publishes a weight-loss multiplier for everyone else, so the calculator does not invent one; the exercise range of 1.4–2.0 g/kg is the reference it states.
Is 200 g of protein a day too much?
Compare it with the ranges for your weight. At 70 kg, 200 g is 2.9 g/kg: inside only the 2.3–3.1 g/kg the ISSN gives for resistance-trained people in a calorie deficit, and above the 1.4–2.0 g/kg (98–140 g) for other exercisers. At 100 kg it is exactly the top of the exercise range. The sources cover healthy adults; with a kidney or liver condition, ask a clinician.
Are 2 eggs enough daily protein?
No. A large hard-boiled egg has 6.3 g of protein (USDA FDC 173424), so two are 12.6 g: under a quarter of the 56 g RDA for a 70 kg adult and about an eighth of the 98 g low end of the exercise range. Reaching 30 g from eggs alone takes almost five; two eggs plus a 170 g Greek yogurt (17.3 g) come to 29.9 g.
How much protein should I eat per meal?
The ISSN suggests 0.25 g of high-quality protein per kg of body weight per serving, or an absolute 20–40 g, evenly spaced every 3–4 hours. At 70 kg that is 17.5 g per serving. The calculator's per-meal table simply divides your daily range by 3, 4 or 5 meals, which lands inside that window for most weights.
Is the protein calculator different for women?
No. All three sources multiply body weight, and none of the passages quoted separates men from women. The 56 g and 46 g in the RDA table are 0.8 g/kg applied to reference weights (56 ÷ 0.8 = 70 kg, 46 ÷ 0.8 ≈ 57 kg), not different rules. Enter your own weight and the result is yours. Pregnancy and breastfeeding are outside these ranges.
Keep reading
How many grams of protein a day? The table by body weight · Low-calorie high-protein foods, ranked · Best protein tracking app in 2026 · How many calories in an egg? · Calorie deficit calculator
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