Free calculator
Protein calculator
Find how many grams of protein you need each day, and per meal, for your body weight, age, activity level and goal. The ranges come from nutrition guidelines and sports nutrition research.
Enter your sex, age, height and weight plus activity level, weekly goal, goal weight. The calculator runs in your browser and nothing is stored.
The formula
Protein (g/day) = body weight (kg) × grams per kg for your goal
- Minimum for adults (RDA): 0.8 g/kg
- Healthy adults over 65: 1.0–1.2 g/kg
- Active adults: 1.2–1.6 g/kg
- Building muscle, or losing weight while keeping muscle: 1.6–2.2 g/kg
- Per meal: about 0.4 g/kg, across three to four meals
With a BMI of 30 or more, the calculator uses the weight at a BMI of 25 (or your goal weight, if lower) so the target stays realistic.
How much protein you need
The official minimum for adults, 0.8 g per kg of body weight, prevents deficiency. It isn't designed for building muscle or dieting. A meta-analysis of 49 strength-training trials found that muscle gains levelled off at around 1.6 g/kg a day, with the upper estimate near 2.2 g/kg. During a calorie deficit, intakes in that range help you keep muscle while you lose fat. The expert PROT-AGE group recommends 1.0–1.2 g/kg for healthy adults over 65.
Example
A 30-year-old who weighs 75 kg, trains three to five times a week and is trying to lose weight:
- Recommended range: 1.6–2.2 g/kg, so 120–165 g a day
- Per meal: about 0.4 × 75 = 30 g, across four meals
At 4 kcal per gram, 120 g of protein is 480 kcal, about a quarter of a 2,000 kcal day.
Why the calculator adjusts for higher body weight
Protein needs follow lean mass more closely than total weight. For someone with a BMI of 30 or more, multiplying total weight by 2 g/kg gives a target that is hard to eat and no more useful. So the calculator bases the grams on the weight at a BMI of 25 for your height, or on your goal weight if that is lower. Many dietitians use the same approach.
Getting enough
- Include a protein source in every meal: eggs, Greek yogurt, cottage cheese, chicken, fish, tofu, tempeh, lentils or beans.
- Spread it across the day, about 20–40 g per meal, rather than eating most of it at dinner.
- Use shakes only if they help. They are convenient, not necessary.
For healthy adults, intakes in these ranges haven't been shown to harm the kidneys. If you have kidney disease, follow your doctor's advice. There are food tables and a sample day in how much protein do you need per day.
Sources
- Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. 2005.
- Morton RW, et al. 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. Br J Sports Med. 2018.
- Jäger R, et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017.
- Bauer J, et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. J Am Med Dir Assoc. 2013.
- Leidy HJ, et al. The role of protein in weight loss and maintenance. Am J Clin Nutr. 2015.
Protein calculator questions
How much protein do I need to build muscle?
About 1.6–2.2 g per kg of body weight a day, combined with progressive strength training. Research shows the benefit levels off around 1.6 g/kg for most people.
How much protein should I eat to lose weight?
At least about 1.6 g/kg, and up to 2.2 g/kg or more if you are lean and training hard. Protein helps preserve muscle and keeps you fuller on fewer calories.
Should I use my current weight or my goal weight?
Use your current weight if you are close to a healthy weight. With a BMI of 30 or more, the calculator uses the weight at a BMI of 25, or your goal weight if that is lower.
Can I eat too much protein?
For healthy adults, intakes up to about 2.2 g/kg have not been shown to be harmful, but there is little extra benefit above that. People with kidney disease should follow medical advice.