Protein Calculator

How to Use the Protein Calculator

Protein is the one macronutrient with a well-supported target, and the target is set by body weight rather than by calories. This calculator turns a grams-per-kilogram figure into a daily total and a sensible per-meal amount.

1. Enter your body weight in kilograms or pounds. The toggle switches which field is shown, and the calculation converts internally.
2. Set a target in grams per kilogram. The table underneath lists what each level suits — 0.8 is the sedentary minimum, 1.6 to 2.2 covers most people who train, and above that is for aggressive cuts.
3. Add a body fat percentage if you carry more than about 25%. The calculator then works from lean mass, which avoids the odd result where total weight demands more protein than the tissue needing it.
4. Set your meals to get the per-meal figure. Muscle protein synthesis responds to a dose rather than a daily total, and 20 to 40 g a sitting is where most of the evidence sits.
5. Add your calorie target to see what share of your intake protein takes. Above roughly 40% the split becomes hard to eat, which is a practical limit rather than a physiological one.

The RDA of 0.8 g/kg is a minimum to prevent deficiency in sedentary adults, not a target for anyone training. Confusing the two is the most common protein error there is.

Protein Formulas

One multiplication, with a choice about what to multiply.

Four kilocalories a gram means protein is never free. A target of 147.6 g contributes 590 kcal — around 27% of a 2,192-calorie day — which has to come out of the carbohydrate and fat allowance. The macro calculator handles that trade explicitly.

Example

82 kg at 1.8 g per kilogram

1. Daily protein: 82 × 1.8 = 147.6 g.
2. Calories from protein: 147.6 × 4 = 590 kcal.
3. As a share of a 2,192-calorie day: 26.9%.
4. Across four meals: 147.6 ÷ 4 = 36.9 g each, which sits nicely inside the 20 to 40 g window.
5. Against the 0.8 g/kg sedentary minimum of 65.6 g, this target is 2.25 times as much.
6. At 18% body fat, lean mass is 67.24 kg, so the same 1.8 g/kg on lean mass would give 121.0 g instead.

Which basis to use

At 18% body fat the two calculations differ by 26.6 g of protein a day — not trivial, and the choice matters more as body fat rises. The usual convention is to use total body weight up to around 25% body fat and switch to lean mass above that, because at higher percentages total weight starts demanding protein for tissue that does not need feeding. Applying 2.2 g per kilogram of lean mass here gives 147.9 g, almost exactly the same answer as 1.8 g/kg of total weight — which is why both conventions coexist happily.

What each level is for

At 0.8 g/kg this body would eat 65.6 g a day, which prevents deficiency and supports nothing. At 1.6 g/kg it reaches 131.2 g, the lower end of what supports muscle growth. At 2.2 g/kg it is 180.4 g — 722 calories, or a third of the day's intake — which is what evidence supports for someone cutting hard while trying to hold onto muscle.

Why the RDA Is Not a Training Target

What each common target works out to at 82 kg.

The gap between the RDA and a training target is more than double, which is the single most important thing on this page. Guidance written for sedentary populations is routinely quoted at people lifting weights four times a week, and it is not the same recommendation.

Above about 2.2 g per kilogram the returns flatten sharply. Studies pushing intake higher generally find no further benefit for muscle growth, though very high intakes appear safe in healthy people with normal kidney function. The practical argument for the higher end is satiety and insurance rather than any anabolic advantage.

Distribution matters alongside the total. Muscle protein synthesis responds to a dose of roughly 0.4 g per kilogram in a sitting — about 33 g here — and a day that delivers 150 g in one enormous evening meal does less than the same total spread across three or four. Four meals of 36.9 g clears that threshold comfortably each time.

Five Practical Points About Hitting It

Five practical points about hitting a protein target.

Cooked and raw weights differ substantially. Meat loses roughly a quarter of its weight cooking, so 150 g of raw chicken becomes about 115 g on the plate with the same protein content. Track consistently in one state or the numbers drift badly.

Plant sources need more attention to variety. Most plant proteins are lower in one or more essential amino acids, particularly leucine, which drives the muscle-building signal. Eating a range across the day resolves this; the older idea that sources must be combined at every single meal does not hold up.

Protein is the most filling macronutrient. That is a genuine advantage on a deficit and a genuine obstacle on a bulk, where hitting a large calorie surplus alongside a high protein target can be uncomfortable.

Kidney concerns apply to existing disease. High protein intake has not been shown to cause kidney damage in healthy people. It does need managing in anyone with existing renal impairment, which is a conversation for a doctor rather than a calculator.

Hitting the target is harder than setting it. One hundred and forty-eight grams is roughly 600 g of cooked chicken breast, or a mix across five or six sources. Working out in advance what a day actually looks like is more useful than refining the target by a tenth of a gram.

Plant sources need a little more attention. Most plant proteins are lower in one or more essential amino acids and are digested slightly less completely, so a plant-based diet is usually advised to aim towards the upper end of the range and to draw from several sources across the day rather than one. Legumes with grains is the classic pairing and it works for exactly this reason.

Older adults need more, not less. The muscle-building response to a given dose of protein blunts with age, which is why guidance for adults over about sixty-five sits nearer 1.2 to 1.5 g/kg even without training. Falling short there contributes directly to the loss of strength and independence that makes later life harder.