Protein Calculator
How much protein to eat a day for your weight, your goal and whether you train, from the research rather than a supplement label, split over your meals.
How active you are
Lightly active · 5,000–7,500 steps a day. A desk job with some walking, or 1–3 workouts a week. × 1.55
More optionsMifflin-St Jeor
From a body-composition scan or scale. It lets you use Katch-McArdle, which works from lean mass.
BMR equation
Why sex? The equations were fitted on people recorded as male or female, so they need one. If neither fits your body, try both: you are likely between the two.
ExampleA 35-year-old woman, 72 kg, 165 cm
115–160g protein a day
1.6–2.2 g per kg of 72 kg.
With kidney disease, ask your doctor before eating more protein.
- Each of 4 meals
- 30–40 g
- Everyday minimum (RDA)
- about 60 g
General information from published research, not a diagnosis or medical advice. Talk to a doctor before changing medication or treatment. An estimate for adults, not for pregnancy or breastfeeding; if eating feels hard or stressful, talk to a doctor. Terms
Your macros115 g protein · 200 g carbs · 60 g fat
Protein at 1.6 g/kg, where extra stopped adding muscle in trials; fat at 30% of calories; carbs the rest.
- Protein115 g26% of calories30 g a meal
- Carbs200 g44% of calories50 g a meal
- Fat60 g30% of calories15 g a meal
For 1,800 kcal a day. Aim for about 25 g of fibre too (14 g per 1,000 kcal).
Calories for your goalTo lose 0.36 kg a week: 1,800 kcal a day
1,800 kcal a day · 400 below maintenance
65 kg in about 19 weeks. Maintenance moves with your weight: about 2,090 kcal at 65 kg, so re-check every few weeks.
The page never goes under 1,200 kcal for women or 1,500 for men, or faster than 1% of your weight (at most 1 kg) a week.
Adjust from your real resultsAfter 2–3 weeks, let your scale correct the estimate
Every equation is an estimate. After a few weeks of eating about the same each day, your weight trend shows your real maintenance: each kilogram lost is about 7,700 kcal your body took from its stores. Use the average of several weigh-ins at each end, since water moves the scale day to day.
Over the last
How this works: Method, 9 sources, Checked against 2 worked examples,
How this works
Method
Protein needs scale with body size, so every recommendation is in grams per kilogram of body weight a day. The question is which number: 0.8 g/kg, the RDA, is the amount that covers almost every adult’s basic needs; people who train, and people losing weight, are better served by more. Full method
Sources
- Jäger et al., International Society of Sports Nutrition position stand: protein and exercise (JISSN, 2017)
- Morton et al., Protein supplementation and resistance training: a meta-analysis of 49 trials (Br J Sports Med, 2018)
- Nutritional priorities to support GLP-1 therapy for obesity: a joint Advisory (Am J Clin Nutr, 2025)
- Dietary Guidelines for Americans, 2020–2025, Appendix 1 (USDA and HHS)
- A new predictive equation for resting energy expenditure in healthy individuals (Mifflin et al.) (Am J Clin Nutr, 1990)
- The Harris Benedict equation reevaluated (Roza and Shizgal) (Am J Clin Nutr, 1984)
- Comparison of predictive equations for resting metabolic rate: a systematic review (Frankenfield et al.) (J Am Diet Assoc, 2005)
- Human energy requirements: report of a joint FAO/WHO/UNU expert consultation (FAO, 2004)
- 2013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults (Circulation, 2014)
How it’s tested
2 worked examples for this page are checked by automated tests before every release: given the inputs, the tool must show the expected answer.
Limits
General information from published research, not a diagnosis or medical advice. Talk to a doctor before changing medication or treatment. An estimate for adults, not for pregnancy or breastfeeding; if eating feels hard or stressful, talk to a doctor.
Changes
- First published: maintenance calories as a range, calories for your goal with a week-by-week timeline, macros and protein, with calorie, macro, BMR and protein calculator pages.
How much protein, and why it depends on you
Protein needs scale with body size, so every recommendation is in grams per kilogram of body weight a day. The question is which number: 0.8 g/kg, the RDA, is the amount that covers almost every adult’s basic needs; people who train, and people losing weight, are better served by more.
Worked example: a woman of 60 kg who lifts weights three times a week and wants to lose fat. Her range is 1.6–2.2 g/kg: 1.6 × 60 = 95 g and 2.2 × 60 = 130 g a day. Over four meals that is about 25–35 g each; if she stopped training, her range would drop to 1.2–1.6 g/kg, or 70–95 g.
The ranges: 1.6–2.2 g/kg when losing weight while training, from the meta-analysis that found gains stopped at about 1.62 g/kg, with 2.2 at the top of its confidence interval; 1.4–2.0 g/kg for most people who exercise, the ISSN’s position; 1.2–1.6 g/kg while losing weight without training; and 0.8–1.6 g/kg otherwise. With a BMI over 27.5 the page uses the weight at a BMI of 27.5 for your height, because grams per kilogram of full weight can overestimate the need.
Protein a day = g per kg × weight (or the weight at BMI 27.5, if lower)
- For building and keeping muscle, 1.4–2.0 g/kg a day is sufficient for most exercising people; 2.3–3.1 g/kg may be needed to keep the most lean mass in resistance-trained people eating less than they burn. Source: Jäger et al., International Society of Sports Nutrition position stand: protein and exercise (JISSN, 2017).
- In 49 trials with 1,863 people, protein beyond 1.62 g/kg a day (95% CI 1.03–2.20) added no further fat-free mass with resistance training. Source: Morton et al., Protein supplementation and resistance training: a meta-analysis of 49 trials (Br J Sports Med, 2018).
- 1.2–1.6 g/kg a day has been proposed during active weight loss, against the adult RDA of 0.8 g/kg. Source: Nutritional priorities to support GLP-1 therapy for obesity: a joint Advisory (Am J Clin Nutr, 2025).
- The adult RDA works out at 46 g of protein a day for women and 56 g for men; protein’s acceptable range is 10–35% of calories. Source: Dietary Guidelines for Americans, 2020–2025, Appendix 1 (USDA and HHS).
Grams of protein a day by body weight
Body weight times each g/kg figure, rounded to 5 g. 0.8 is the RDA; 1.6 is where extra stopped adding muscle in trials; 2.2 is the top of that estimate.
| Body weight | 0.8 g/kg | 1.2 g/kg | 1.6 g/kg | 2.0 g/kg | 2.2 g/kg |
|---|---|---|---|---|---|
| 50 kg (110 lb) | 40 g | 60 g | 80 g | 100 g | 110 g |
| 60 kg (132 lb) | 50 g | 70 g | 95 g | 120 g | 130 g |
| 70 kg (154 lb) | 55 g | 85 g | 110 g | 140 g | 155 g |
| 80 kg (176 lb) | 65 g | 95 g | 130 g | 160 g | 175 g |
| 90 kg (198 lb) | 70 g | 110 g | 145 g | 180 g | 200 g |
| 100 kg (220 lb) | 80 g | 120 g | 160 g | 200 g | 220 g |
| 110 kg (243 lb) | 90 g | 130 g | 175 g | 220 g | 240 g |
| 120 kg (265 lb) | 95 g | 145 g | 190 g | 240 g | 265 g |
Frequently Asked Questions
How much protein do I need a day?
At least 0.8 g per kilogram of body weight, the RDA. If you exercise, 1.4–2.0 g/kg is the ISSN’s range, and while losing weight with strength training, 1.6–2.2 g/kg helps keep muscle. For a 70 kg person that is 56 g, 100–140 g and 110–155 g a day.
How much protein to build muscle?
About 1.6 g/kg a day. A meta-analysis of 49 trials found that beyond 1.62 g/kg, extra protein added no more muscle with resistance training, though some people may benefit up to about 2.2. Training is what builds the muscle; protein lets it.
Can I eat too much protein?
More than about 2.2 g/kg rarely adds anything for muscle: that was the top of the meta-analysis’s estimate. The ISSN discusses 2.3–3.1 g/kg only for trained people dieting hard. The 2025 joint advisory on nutrition with GLP-1 medicines suggests avoiding long-term intakes at or above 2 g/kg in that setting. With kidney disease, ask your doctor first.
Should I use my current weight or goal weight?
Your current weight, unless your BMI is over 27.5: then grams per kilogram of full weight can overestimate the need, and the page uses the weight at a BMI of 27.5 for your height instead. If you know your lean mass from a scan, protein per kilogram of lean mass is another option.