Protein Intake Calculator
Find how much protein you need a day in grams, based on your weight, activity and goal: maintain, lose fat or build muscle. Uses expert g/kg guidelines.
🥩 Protein Intake
Daily Protein
💡 How Much Protein Do You Need a Day?
This calculator multiplies your body weight by a protein target in grams per kilogram (g/kg) that depends on your goal and activity level, and gives a range of ±0.2 g/kg around it. For a 70 kg person who is moderately active and wants to maintain weight, the target is 70 g of protein a day (1 g/kg), with a range of 56–84 g.
How the target is set
Range = body weight × (factor − 0.2) to body weight × (factor + 0.2)
| Goal | Activity | Factor | Range | For 70 kg |
|---|---|---|---|---|
| Maintain | Sedentary, light or moderate | 1.0 g/kg | 0.8–1.2 g/kg | 70 g (56–84) |
| Maintain | Active or very active | 1.4 g/kg | 1.2–1.6 g/kg | 98 g (84–112) |
| Lose fat | Any | 1.6 g/kg | 1.4–1.8 g/kg | 112 g (98–126) |
| Build muscle | Sedentary, light or moderate | 1.8 g/kg | 1.6–2.0 g/kg | 126 g (112–140) |
| Build muscle | Active or very active | 2.2 g/kg | 2.0–2.4 g/kg | 154 g (140–168) |
Worked examples
- 70 kg, moderate activity, maintain: 70 × 1.0 = 70 g (range 70 × 0.8 = 56 g to 70 × 1.2 = 84 g).
- 70 kg, losing fat: 70 × 1.6 = 112 g a day.
- 80 kg, active, building muscle: 80 × 2.2 = 176 g a day.
What the research recommends
| Who | Recommendation | Source |
|---|---|---|
| Healthy adults (minimum to avoid deficiency) | 0.8 g/kg a day (RDA) | U.S. Institute of Medicine, 2005 |
| Healthy adults over 65 | At least 1.0–1.2 g/kg a day | PROT-AGE Study Group, 2013 |
| Athletes | 1.2–2.0 g/kg a day | ACSM, Academy of Nutrition and Dietetics and Dietitians of Canada, 2016 |
| Most exercising people | 1.4–2.0 g/kg a day | International Society of Sports Nutrition, 2017 |
The RDA of 0.8 g/kg is the amount that meets the basic needs of nearly all healthy adults. It is a minimum, not an optimal amount for people who train. The calculator's lowest setting, 1.0 g/kg, sits a little above it.
How much protein builds muscle?
A 2018 meta-analysis in the British Journal of Sports Medicine pooled 49 trials with 1,863 participants doing resistance training. Extra protein increased gains in muscle mass, but the benefit levelled off at a total intake of about 1.6 g/kg a day. The exact point is uncertain: its 95% confidence interval ran from about 1.0 to 2.2 g/kg, so aiming up to 2.2 g/kg is a reasonable way to make sure most people get the full benefit. That matches the calculator's muscle-building settings of 1.8 and 2.2 g/kg. Training itself matters most: protein supports muscle growth but cannot replace resistance exercise.
Protein needs by body weight
Grams per day at common targets:
| Body weight | 0.8 g/kg (RDA) | 1.0 g/kg | 1.6 g/kg | 2.2 g/kg |
|---|---|---|---|---|
| 50 kg | 40 | 50 | 80 | 110 |
| 60 kg | 48 | 60 | 96 | 132 |
| 70 kg | 56 | 70 | 112 | 154 |
| 80 kg | 64 | 80 | 128 | 176 |
| 90 kg | 72 | 90 | 144 | 198 |
| 100 kg | 80 | 100 | 160 | 220 |
Protein when losing weight
When you eat fewer calories, part of the weight lost can be muscle. A higher protein intake, combined with strength training, helps keep it, and protein is also the most filling macronutrient. The calculator uses 1.6 g/kg for fat loss, within the 1.4–2.0 g/kg range the ISSN recommends; the ISSN notes that resistance-trained people cutting calories may benefit from more. To plan calories alongside protein, use the calorie calculator and the macro calculator.
Should I use my current weight or goal weight?
The g/kg guidelines come mainly from studies of people at a healthy weight. If you carry a lot of body fat, multiplying your total weight can give a very high number. Many dietitians use your goal weight or ideal body weight instead, or base protein on lean mass with the lean body mass calculator.
Spreading protein through the day
The ISSN suggests about 0.25 g/kg per meal, or roughly 20–40 g, every 3–4 hours. For the 70 kg example, 70 g a day over three meals is about 23 g each.
Typical protein content (USDA values, approximate):
| Food | Amount | Protein |
|---|---|---|
| Chicken breast, cooked | 100 g | about 31 g |
| Egg | 1 large | about 6 g |
| Greek yoghurt, plain | 100 g | about 10 g |
| Lentils, cooked | 100 g | about 9 g |
Is high protein safe?
For healthy adults, intakes within the ranges above are widely used in research and sports nutrition. People with chronic kidney disease are different: the PROT-AGE group, for example, excludes older people with severe kidney disease not on dialysis from its higher targets, as they may need to limit protein. If you have kidney or liver disease, are pregnant or breastfeeding, or have another medical condition, follow your doctor's or dietitian's advice.
This calculator is designed for healthy adults and isn't suitable for children.
Sources
- Jäger R, 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, 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, 376–384
- Thomas DT, Erdman KA, Burke LM (2016). Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and athletic performance. Journal of the Academy of Nutrition and Dietetics, 116(3), 501–528.
- Bauer J, et al. (2013). Evidence-based recommendations for optimal dietary protein intake in older people: PROT-AGE Study Group. Journal of the American Medical Directors Association, 14(8), 542–559
- Institute of Medicine (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press.
- USDA FoodData Central (food protein values)