How much protein do you actually need?

Almost every protein recommendation you will find is a single number, and almost every one of them is wrong for somebody. The useful answer is a range in grams per kilogram of body weight, and which part of the range you want depends on your goal rather than on any single study.

The ranges this site uses

The protein calculator uses the same three targets throughout, and they come from strength-sport training nutrition rather than clinical intake guidance:

Goal	Grams per kg of body weight	Why it moves
General / maintain	1.2–1.6 g/kg	Enough to maintain muscle at a normal intake.
Lose weight	1.6–2.0 g/kg	Higher, to hold on to lean mass while in a calorie deficit.
Build muscle	1.6–2.0 g/kg	Higher, to support growth and recovery.

Where more stops helping

The ranges top out at 2.0 g/kg, and that ceiling is deliberate. There is little evidence that going substantially higher improves muscle growth or fat loss in people who are already training hard. Past the top of the range you are mostly adding cost, and in some cases discomfort, for no measurable gain.

That is a training-nutrition ceiling, not a safety limit. It is well below what someone with a kidney condition might be told to stay under, which is exactly the point: the two limits are different numbers for different reasons, and this page is only claiming the first one.

How to turn grams into an actual target

The calculator returns three numbers: a lower and upper bound from your goal range, and a recommended target at the midpoint. Use the midpoint as your daily number. If you are at the lower end of a range, or you find the upper end hard to hit, the midpoint is still a good answer rather than a failure.

Once you have a gram target, the macro calculator will split a calorie target into protein, carbohydrate and fat, with protein held at the figure above and the rest divided around it. That is the useful order of operations: decide calories, decide protein, then split what is left.

What this does not account for

These are estimates for generally healthy adults. No adjustment is made for kidney disease, pregnancy, or any other clinical condition — the calculator collects age, sex, height and activity so the form matches the others, but none of them change the protein maths, which depends on body weight and goal alone. If you have a medical condition that affects protein metabolism, a clinician should set your target, not this page.

Sources

Kleiner M. Energy and macronutrient requirements of strength athletes: an update. International Journal of Sport Nutrition and Exercise Metabolism. 2015;25(3):279-287.
Used for: Macro splits by goal, and the protein ranges used across the site. These are training-nutrition ranges, not clinical intakes.
National Health Service. How to lose weight. NHS Health Check.
Used for: Safe, gradual rate-of-weight-change framing, and the 0.5-1 kg per week range most guidance supports.