Protein Intake Calculator
Estimate daily protein in grams from evidence-backed adult and exercising profiles, with an athlete-only fat-free-mass option.
Results
How much protein do I need a day?
This protein calculator answers that in grams of protein a day, from your body weight and the profile that describes you. It reports a range rather than one figure, because the guidance it draws on is published as a range and a single number would be false precision.
Enter weight in kilograms or pounds; the protein intake calculator converts once and works in kilograms from there, so both unit systems return the same answer for the same body. Alongside the daily grams it shows the grams-per-kilogram range used, which profile supplied it, and the calories that much protein represents at 4 kcal per gram.
The three profiles
Which range applies depends on the profile, and the difference between them is large enough that picking the wrong one matters more than any rounding:
| Profile | Range | Per pound or basis |
|---|---|---|
| General healthy adult | 0.8 g per kg of body weight | About 0.36 g per pound |
| Exercising adult | 1.4 to 2.0 g per kg of body weight | About 0.64 to 0.91 g per pound |
| Energy-restricted athlete | 2.3 to 3.1 g per kg of fat-free mass | Requires a body fat percentage |
General healthy adults use the longstanding 0.8 grams per kilogram of body weight reference. Exercising adults use the broader 1.4 to 2.0 grams per kilogram range commonly cited for training. The energy-restricted athlete profile is narrower in audience and applies 2.3 to 3.1 grams per kilogram of fat-free mass, which is why it asks for body fat instead of guessing lean mass from a formula.
The first two are calculated against total body weight. Only the third is calculated against fat-free mass, so its grams-per-kilogram figures are not comparable with the other two and should not be read side by side as though they were.
What this calculator does not do
This page does not build a full diet plan, estimate calories, or claim a single precise gram target for every sport, age, or medical condition. It stays inside the healthy-adult profiles listed above, shows the range rather than a fake exact answer, and leaves calorie targets to the separate calorie calculator.
It also makes no claim about what a given intake will produce. Protein is one input into training outcomes, body composition and recovery, and this tool estimates an intake range only.
Sources and limitations
Sources reviewed 27 August 2026. This is an educational estimate for healthy adults and not medical or dietary advice. Body-fat based output is only as reliable as the body fat percentage entered.
It is not intended for children or adolescents, during pregnancy or breastfeeding, or for anyone with kidney disease or another condition that changes protein needs. Those cases need individual clinical advice, which a calculator cannot give.
Frequently asked questions
How much protein do I need each day?
It depends on which evidence-backed profile fits you. This calculator uses body weight for general and exercising adults, and fat-free mass only for energy-restricted resistance-trained athletes.
How much protein do I need a day?
It depends which profile describes you. The general adult reference is 0.8 grams per kilogram of body weight a day, so an 80 kg adult is at about 64 grams. Adults who train regularly are commonly given 1.4 to 2.0 grams per kilogram, which for the same person is roughly 112 to 160 grams. This protein calculator reports the range rather than a single figure, because the evidence is a range.
How many grams of protein per pound?
The same guidance converted: 0.8 grams per kilogram is about 0.36 grams per pound, and the 1.4 to 2.0 range is about 0.64 to 0.91 grams per pound. The calculator works in kilograms internally and converts your entry once, so pounds and kilograms return the same answer for the same body.
Why does the athlete profile ask for body fat?
Because it is the only profile calculated against fat-free mass rather than total body weight. Its 2.3 to 3.1 grams per kilogram range is defined that way in the literature it comes from, so applying it needs a lean-mass figure, and the calculator asks for a measured body fat percentage instead of guessing one from a formula.
Does eating more protein build muscle on its own?
No. Protein intake is one input among several, and this calculator estimates an intake range only. It does not model training, total energy intake, or any other factor, and it does not claim that a figure at the top of a range produces a better outcome than one lower in it.
How many calories are in the protein target?
Protein carries 4 kcal per gram, so the calculator shows the calorie range your protein target represents. It is given for context only. This page does not turn it into a full calorie target or a macronutrient split, which the calorie calculator does instead.