Protein Intake Calculator

Enter your body weight in kilograms, choose a goal, and this returns a daily protein target in grams. Those are the only two inputs — there is no unit conversion, no height, no age, and no sex. The value of the page is in the multiplier it picks and why.

Four multipliers, and where each comes from

Sedentary / general health      0.8 g per kg of body weight
Endurance training              1.4 g/kg
Strength training, muscle gain  1.8 g/kg
Fat loss, preserving muscle     2.0 g/kg

An 80 kg lifter selecting the strength goal gets 80 x 1.8 = 144 g a day. The tool also shows what that costs in energy — protein supplies 4 kcal per gram, so 576 kcal — and divides it across four meals at 36 g each.

The 0.8 g/kg figure is the US recommended dietary allowance; the European Food Safety Authority's dietary reference values put the equivalent population reference intake at 0.83 g/kg for adults. Both are derived from nitrogen balance studies and answer one question: how little protein prevents deficiency in a sedentary adult. That is not the same question as how much supports training, and treating the RDA as an optimum is the single most common error in this area.

For resistance training, the International Society of Sports Nutrition's 2017 position stand recommends 1.4 to 2.0 g/kg to build and maintain muscle mass. The 2018 meta-analysis by Morton and colleagues in the *British Journal of Sports Medicine* found that gains in fat-free mass plateaued at about 1.62 g/kg per day, with a wide confidence interval that reaches well above 2 g/kg — which is why 1.8 sits where it does rather than at the point estimate.

The fat-loss multiplier is higher on purpose. Helms and colleagues (2014) reviewed protein needs of lean, resistance-trained athletes in an energy deficit and recommended intakes at the upper end of the usual range, because a deficit is when lean mass is most at risk and because protein is the most satiating macronutrient per calorie.

Note that a goal must be selected. An earlier build silently fell back to the 0.8 g/kg sedentary factor whenever the default was left untouched, so lifters who never opened the dropdown were handed the deficiency-prevention figure. That default is fixed.

What the target is calculated from, and why that matters

The multiplier is applied to total body weight. For most people that is fine. For someone carrying a lot of fat mass it over-states the requirement, because adipose tissue has little protein turnover — lean body mass, or an adjusted body weight, is the better basis, and a 120 kg person at 40% body fat would be better served scaling from roughly 72 kg of lean tissue than from 120.

Distribution matters alongside the total. Roughly 0.4 g/kg per meal across three or four meals is better used for muscle protein synthesis than the same daily total taken in one sitting, which is why the per-meal figure is shown next to the daily one.

The limits worth knowing

Higher protein intakes are well tolerated by healthy kidneys, and the claim that they damage normal renal function is not supported. Existing kidney disease is a different matter entirely: intake there is set by a nephrologist, often deliberately restricted, and nothing on this page applies. The same caution covers liver disease and inherited disorders of amino acid metabolism.

The ranges above come from sport-science research on adults. They are not calibrated for children, for pregnancy, or for clinical situations such as recovery from major surgery, where requirements are higher and supervised. Older adults may need more than the RDA to overcome anabolic resistance, but the athletic bands here are not the right instrument for that either.

Protein is also only part of an intake plan. To see how a protein target fits alongside carbohydrate and fat within a calorie budget, use the macro calculator; to work out what that calorie budget should be, the calorie calculator estimates it from your measurements and activity.

The calculation runs in your browser and your weight is not transmitted anywhere, though your own browser may remember it. This page has not been reviewed by a dietitian or a doctor.