Protein Calculator

The Recommended Dietary Allowance for protein is 0.8 grams per kilogram of body weight per day, which works out to about 0.36 grams per pound. That figure is frequently misread as an optimal intake. It is not. The RDA is the minimum required to prevent deficiency in the majority of sedentary adults — the floor below which nitrogen balance turns negative, not the level that supports training, aging muscle, or fat loss.

Research on resistance-trained populations consistently lands between 1.6 and 2.2 grams per kilogram (roughly 0.7 to 1.0 grams per pound) for people who lift regularly. A widely cited 2018 meta-analysis of 49 studies found muscle-protein gains plateaued around 1.6 g/kg per day, with the confidence interval extending to about 2.2 g/kg. Above that range, additional protein does not appear to add muscle, though it is not harmful in healthy people.

Two situations justify pushing toward the top of the range or beyond. The first is an aggressive calorie deficit: when energy is scarce, the body will strip amino acids from muscle unless dietary protein is high, so cutting athletes often run 2.3 to 3.1 g/kg of fat-free mass. The second is aging. Adults over about 60 experience anabolic resistance, meaning a given dose of protein triggers less muscle synthesis than it did at 25, so 1.2 to 1.6 g/kg is a reasonable floor rather than a ceiling for older adults.

Endurance athletes sit between the two. Marathoners, cyclists, and triathletes need more than sedentary adults because of amino acid oxidation during long sessions and the repair demand afterward — typically 1.2 to 1.6 g/kg — but they do not need the intake a hypertrophy-focused lifter uses.

For people in a normal body-fat range, using total body weight is fine and simpler. Fat tissue has a small but non-zero protein requirement, and the difference between the two methods at 15% body fat is only a few grams per day.

The methods diverge sharply at higher body fat. A 300-pound person with 40% body fat who uses 1.0 g per pound of total weight lands at 300 grams of protein per day — an intake that is expensive, hard to eat, and displaces the carbohydrates and fats that make a diet sustainable. Basing the target on lean mass instead gives 180 grams, which is more than adequate.

The practical rule: if your body fat is above roughly 25% for men or 32% for women, calculate from lean body mass or from your goal weight rather than your current weight. This calculator shows both numbers so you can see the spread and choose deliberately.

Do not overthink the precision. Protein requirements are a plateau, not a knife edge. Landing anywhere inside a 30-gram window of the target produces the same result, which is why the calculator reports a range rather than a single number pretending to two-decimal accuracy.

Muscle protein synthesis responds to a dose, not just a daily total. Each feeding of roughly 0.4 grams per kilogram of body weight — about 25 to 40 grams for most adults — maximally stimulates synthesis for a few hours, after which the response returns to baseline regardless of how much more protein is in the bloodstream.

That physiology argues for spreading intake across three to five feedings rather than eating 30 grams at breakfast, 20 at lunch, and 150 at dinner. Controlled studies comparing even distribution against skewed distribution at matched totals generally favor the even pattern for muscle retention, though the effect is modest compared with simply hitting the daily total.

The leucine threshold is the mechanism. Leucine is the amino acid that triggers the mTOR pathway, and roughly 2.5 to 3 grams of leucine per meal is needed to flip the switch. Animal proteins hit that with a normal serving; plant proteins usually need a larger portion or a blend, because most are lower in leucine and one or more essential amino acids.

Pre-sleep protein is a small but real edge for people training hard. Around 30 to 40 grams of a slow-digesting protein such as casein or cottage cheese before bed measurably raises overnight synthesis rates without disrupting sleep.

A 175-pound (79.4 kg) person trains with weights four times a week and wants to lose fat. Moderate training gives a base of 1.6 g/kg, and a fat-loss goal adds 0.35, for 1.95 g/kg — about 155 grams of protein per day, with a practical working range of roughly 135 to 175 grams.

That protein alone supplies about 620 calories. If the person's total daily target during the cut is 2,100 calories, protein takes 30% of the budget, leaving about 1,480 calories to split between carbohydrates and fat, which is comfortable.

Split across four meals, that is roughly 39 grams each — for example, 6 ounces of chicken breast, a cup of Greek yogurt with a scoop of whey, 6 ounces of salmon, and a bowl of lentils with cottage cheese. None of those portions are unusual, which is the point: a well-set protein target should be reachable with normal food.

At 20% body fat this person carries about 63.5 kg of lean mass. Calculating 2.2 g per kg of lean mass instead gives 140 grams, sitting comfortably inside the range above. When the two methods agree, you have a target you can trust.

Protein quality is measured by digestibility and amino acid profile. Whey, eggs, dairy, beef, poultry, fish, and soy all score at or near the top of the DIAAS and PDCAAS scales, meaning nearly all of what you eat is absorbed and usable. Wheat, rice, and most legumes score lower because each is limited in a specific essential amino acid — lysine in grains, methionine in beans.

Combining sources solves this without any need to do it within a single meal. Rice and beans, hummus and pita, or a pea-and-rice protein blend together provide a complete amino acid profile. Total daily intake is what matters; the old advice about pairing at every meal has not held up.

Plant-based eaters should aim for roughly 10 to 20 percent more total protein than the calculated target to offset lower digestibility and leucine content. On a 150-gram target, that means about 165 to 180 grams. Soy, pea protein isolate, seitan, tempeh, and lentils carry most of the load efficiently.

High protein intake in healthy people with normal kidney function has been studied extensively and does not damage the kidneys. Intakes above 2 g/kg sustained for years show no adverse effect on kidney or liver markers in trained adults. People with existing chronic kidney disease are the genuine exception and should follow a nephrologist's prescription instead of a general calculator.