Protein Calculator

Worked example

A 75 kg adult doing nothing in particular needs 60 g of protein a day by the RDA — the amount that prevents deficiency in nearly everyone. Someone strength training is usually given 1.6 g/kg, which is twice that, and the two figures answer different questions.

How to work it out yourself

1. 1.Enter your weight and what you actually do. The RDA and a training target are not competing estimates of the same thing: one is a floor, the other is an optimum for a goal.
2. 2.Use lean mass rather than total weight if you carry a lot of fat — protein needs scale with the tissue that uses it, and body weight overstates the requirement at high body fat.
3. 3.Spread it across the day. Absorption is not the limit people think, but four meals of 30 to 40 g is easier to eat than one of 150.

The formula

1. RDA floor, 0.8 g/kg75 * 0.8
2. Grams per kg for this goal
3. Daily protein75 * 0.8
4. Lower end of the range75 * 0.8
5. Upper end of the range75 * 1
6. Lean body mass
7. Grams per kg of lean mass
8. Calories from that protein60 * 4
9. Share of your daily calories240 / 2200 * 100
10. Per meal across four meals60 / 4

Source: National Academies — Dietary Reference Intakes: The Essential Guide to Nutrient Requirements, US Dietary Guidelines for Americans

Questions people actually ask

Is the RDA the amount I should eat?

It is the amount below which deficiency becomes likely, set to cover 97.5% of healthy adults — 0.8 grams per kilogram a day. It is a floor rather than a target, and it was never derived for people training, dieting or over sixty-five. Reading it as "the right amount" is the single most common misuse of a Dietary Reference Intake.

How much protein for building muscle?

The training literature converges on roughly 1.6 grams per kilogram a day, with little further benefit above about 2.2 in most studies. In pounds that is around 0.7 to 1.0 per pound of body weight, which is where the gym rule of thumb comes from. More than that is not harmful in healthy people, it simply stops adding anything.

Do I need more protein when losing weight?

Yes, proportionally more than at maintenance. In a calorie deficit, protein preserves lean tissue that would otherwise be broken down, and it is the most satiating of the three macronutrients. Intakes around 2.0 to 2.4 g per kg of body weight are common in the literature on dieting while training.

Is too much protein bad for your kidneys?

In people with healthy kidneys there is no good evidence of harm from intakes in this range, and controlled trials at two to three times the RDA have not shown damage. In existing kidney disease it is a different question entirely, and intake is a clinical decision rather than a calculator one.

Related

• Macro CalculatorGrams of protein, carbohydrate and fat from a calorie target and a diet split. With protein per kilogram, the number a split is judged on.
• TDEE CalculatorHow many calories you burn in a day, from the Mifflin-St Jeor equation and an activity multiplier, with cut and bulk targets beside it.
• BMR CalculatorBasal metabolic rate from the Mifflin-St Jeor, revised Harris-Benedict and Katch-McArdle equations at once, with the disagreement between them shown.
• One Rep Max CalculatorYour one-rep max from a set to failure, by all four published formulas at once, with the spread between them and how far they run high.
• Fat Intake CalculatorHow many grams of fat a day your calorie intake allows, inside the 20-35% range the Dietary Guidelines set, with the saturated fat ceiling separately.
• Calories Burned CalculatorEnergy burned by an activity from its MET value, body weight and duration. Net of what you would have burned sitting still, which trackers leave in.

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