Free Protein Intake Calculator: How Much Do You Need?

The Recommended Dietary Allowance for protein is 0.8 grams per kilogram of body weight — about 0.36 grams per pound. For a 180 pound adult that's roughly 65 grams a day.

It's worth understanding what that figure is for. The RDA is set at the level that prevents deficiency in the large majority of sedentary adults. It is a minimum to avoid a problem, not an amount optimized for building muscle, recovering from training, or staying strong as you age. Treating it as a target is the single most common misreading in this area.

Published sports nutrition positions converge on these ranges for healthy adults:

Fat loss taking the top of the range surprises people, but the logic is sound. In a calorie deficit your body is looking for tissue to break down, and higher protein intake alongside resistance training tilts that toward fat rather than muscle. Protein is also the most filling macronutrient per calorie, which makes the deficit easier to hold.

Protein needs are driven by lean tissue, not fat tissue. For someone at an average body composition the distinction barely matters — but for someone carrying higher body fat, scaling protein to total body weight inflates the target considerably.

A 250 pound person at 35% body fat calculating for fat loss gets about 238 grams a day on total weight, but about 195 grams on lean mass. The second number is the more defensible one, and it's a lot easier to eat. If you know your body fat percentage, switch the basis under Advanced options — or estimate it first with our body fat calculator.

Muscle protein synthesis — the process that builds and repairs muscle tissue — is triggered by a meal containing enough protein, then returns to baseline a few hours later. Eating protein at several points across the day triggers that response several times. Eating the same total in one sitting triggers it once.

Research comparing even distribution against skewed distribution at matched daily totals consistently favours the even approach, though the effect is modest compared with simply hitting your daily number. Get the total right first, then improve the distribution.

Roughly 20–40 grams of quality protein per meal is the practical window. Around 20 grams appears to be the point where the muscle-building response is meaningfully triggered for most younger adults; older adults generally need more, closer to 30–40 grams, because muscle becomes less responsive to protein with age.

The old idea that the body can only absorb 20–30 grams at a sitting is a misreading. You absorb essentially all the protein you eat — what plateaus is the muscle-building signal specifically, not absorption. Larger meals are not wasted; the surplus simply goes to other uses.

Practical version: four meals of 35–45 grams is easier to hit and more effective than one enormous dinner. The per-meal breakdown in the calculator does that division for you.

A complete protein contains all nine essential amino acids in useful amounts. Animal sources — meat, fish, eggs, dairy — are complete, as are soy and quinoa among plant foods. Most other plant sources are lower in one or more essential amino acids, typically lysine in grains and methionine in legumes.

The advice to carefully combine plant proteins within a single meal is outdated. Your body maintains a pool of amino acids and draws on it across the day, so eating a variety of plant proteins over the course of a day is sufficient. Rice and beans at the same sitting is fine, but so is rice at lunch and beans at dinner.

Plant proteins are also somewhat less efficiently used than animal proteins, so people eating entirely plant-based diets are often advised to aim toward the higher end of their range — roughly 10–20% above the equivalent target.

Protein needs rise with age rather than falling. Muscle becomes less responsive to protein over time — a phenomenon called anabolic resistance — meaning older adults need more protein to produce the same muscle-building response.

Expert consensus recommends a minimum of 1.0–1.2 g/kg for adults over 65, rising toward 1.2–1.5 g/kg for those who are active or managing illness. Since age-related muscle loss is one of the strongest predictors of losing independence in later life, this is arguably the population for whom getting protein right matters most. The calculator raises the floor automatically for anyone 65 or older.

The concern that high protein damages the kidneys comes from advice given to people who already have kidney disease, where restricting protein slows progression. That guidance was generalized to the healthy population, where the evidence does not support it. Controlled studies in healthy adults consuming high protein intakes over extended periods have not found kidney damage.

The caveats are genuine but narrow. If you have existing kidney disease, follow the intake your doctor sets rather than a calculator. And very high protein intakes displace other foods — pushing protein so high that vegetables, fruit, and fibre get squeezed out creates a different problem.

Protein requirements increase during pregnancy and breastfeeding, typically by around 25 grams a day over baseline. This calculator isn't built for either situation — needs vary through the stages of pregnancy and are best set with a doctor or registered dietitian.

To fill in the rest of the picture, try our macro calculator for full calorie and macronutrient targets, our lean body mass calculator, or browse everything on the tools page.