How to use the protein calculator
Enter your weight in pounds or kilograms and pick the reference that fits your question. The result shows a daily range, its midpoint, an even per-meal split, and how many calories the protein supplies. The calculator converts pounds to kilograms first, so both units give the same answer.
The two optional fields don't change your range. Daily calories show what share of your energy the protein makes up. Current intake compares your food log with the range.
- Choose kilograms or pounds and enter your current body weight.
- Pick a reference: adult RDA (0.8 g/kg), U.S. guideline (1.2-1.6 g/kg), exercise research (1.4-2.0 g/kg), or a custom range.
- Set how many times a day you eat if you want a per-meal split.
- Optionally add daily calories and your current protein intake.
- Press Calculate and read the range, midpoint, per-meal amounts and comparison table.
How much protein per day by body weight
Here are the three built-in references worked out for common body weights. Pounds are converted to kilograms before multiplying. In pounds, the guideline range works out to about 0.54 to 0.73 g per pound, and the RDA to about 0.36 g per pound.
| Body weight | RDA (0.8 g/kg) | U.S. guideline (1.2-1.6 g/kg) | Exercise (1.4-2.0 g/kg) |
|---|---|---|---|
| 120 lb (54.4 kg) | 44 g | 65-87 g | 76-109 g |
| 140 lb (63.5 kg) | 51 g | 76-102 g | 89-127 g |
| 160 lb (72.6 kg) | 58 g | 87-116 g | 102-145 g |
| 180 lb (81.6 kg) | 65 g | 98-131 g | 114-163 g |
| 200 lb (90.7 kg) | 73 g | 109-145 g | 127-181 g |
| 220 lb (99.8 kg) | 80 g | 120-160 g | 140-200 g |
Worked example for a 75 kg adult
At 75 kg, the U.S. guideline range of 1.2 to 1.6 g/kg gives 90 to 120 g of protein a day, with a midpoint of 105 g. Split evenly over four meals, that's 22.5 to 30 g each. At 4 calories per gram, the range is 360 to 480 calories.
Add a 2,200-calorie day and protein makes up about 16.4% to 21.8% of calories. That sits well inside the adult range of 10% to 35% of calories from protein.
| Reference | Daily protein | Four even meals | Protein calories |
|---|---|---|---|
| Adult RDA: 0.8 g/kg | 60 g | 15 g each | 240 kcal |
| U.S. guideline: 1.2-1.6 g/kg | 90-120 g | 22.5-30 g each | 360-480 kcal |
| Exercise: 1.4-2.0 g/kg | 105-150 g | 26.3-37.5 g each | 420-600 kcal |
The protein formula
The math is a single multiplication, done for both ends of the range. The calculator keeps full precision inside and rounds only the grams you see.
Weight in kg = weight in pounds / 2.2046226218Daily protein = weight in kg x g/kg rate (low and high)Protein per meal = daily protein / number of mealsProtein calories = protein grams x 4
Protein to build muscle
Pick the exercise reference. The International Society of Sports Nutrition describes 1.4 to 2.0 g/kg a day as enough for most healthy people who exercise. A large meta-analysis found that, on average, extra protein stopped adding muscle gains from resistance training at about 1.62 g/kg a day.
Protein alone doesn't build muscle. You still need the training, enough calories and recovery. For per-meal amounts, the ISSN discusses about 0.25 g/kg or 20 to 40 g of quality protein per serving, spread every three to four hours.
Protein for weight loss
When you eat less, setting protein in grams per kilogram keeps it from shrinking along with your calories. The ISSN position stand notes that resistance-trained people may need 2.3 to 3.1 g/kg a day to hold on to the most lean mass while dieting. You can enter that as a custom range.
This calculator doesn't set a calorie target or predict weight loss. Use it to fix your protein grams, then plan calories with a macro or calorie deficit tool. If you have kidney disease, let your doctor or a renal dietitian set your protein.
When a general protein number isn't enough
The National Academies didn't set an upper limit for protein because the evidence was too thin. That doesn't prove very high intakes are safe, so a custom range above 2.0 g/kg should have a clear reason behind it.
Don't use this adult tool for children, pregnancy or breastfeeding, kidney or liver disease, dialysis, recovery from serious illness, or a prescribed diet. NIDDK notes that protein needs change with chronic kidney disease and dialysis, and those amounts should come from your care team.
Sources
These references back up the protein rates, the muscle and dieting figures, and the medical limits on this page.