Protein Calculator: How Much Protein Do You Need?

How to use this protein calculator

Choose Metric (kilograms) or Imperial (pounds).
Enter your body weight.
Pick the goal that matches your life right now — the grams per kilogram change a lot between them.
Read the large figure: your daily protein target, with a sensible range and a per-meal split underneath.

Why protein is set per kilogram

Protein needs scale with the body that uses it: muscle is built and repaired in proportion to lean tissue, so recommendations are written as grams per kilogram of body weight. A single flat figure — "eat 100 g" — undershoots a 95 kg lifter and overshoots a 55 kg office worker.

The other dial is goal. The official RDA of 0.8 g/kg is a floor for sedentary adults, set to prevent deficiency. Training, dieting and ageing all raise the useful range, which is why this page asks what you are actually doing before it gives a number.

The numbers behind it

Grams per kilogram, by goal

Everyday 0.8 · Active 1.4 · Build muscle 1.8 · Lose fat 2.2 g/kg

Drawn from the ranges sports-nutrition research keeps landing on: about 1.6–2.2 g/kg for muscle gain, higher still per kilo when dieting, because a deficit is when muscle is at risk.

The range

Target ± 0.2 g/kg

Nobody's true need is a single gram. The page shows a band around the target; landing anywhere inside it, most days, is the whole job.

Per meal

Daily grams ÷ 3 meals

Muscle protein synthesis responds best to protein spread through the day — roughly 0.4 g/kg per meal. The per-meal figure makes the daily target plannable.

Examples

Person	Factor	Daily protein	Per meal
80 kg, building muscle	1.8 g/kg	144 g	48 g
65 kg, active	1.4 g/kg	91 g	30 g
95 kg, losing fat	2.2 g/kg	209 g	70 g

Four protein mistakes

All of it in one meal

A tiny breakfast and a 120 g dinner is worse than the same grams spread out. Aim for a real protein portion at each meal.

Counting grams, ignoring the day

Protein inside a day that is 1,000 kcal over target still gains fat. The Macro Calculator exists to set the protein inside the whole day, not beside it.

Powder over food

Shakes are convenient protein, not better protein. Food first — eggs, dairy, meat, fish, soy, legumes — and powder for the gaps life leaves.

Never adjusting

Lose 10 kg or stop training and the target moves with you. Recalculate when your weight or goal changes, not once forever.

Frequently asked questions

Is the RDA of 0.8 g/kg enough?

It is the minimum to avoid deficiency for sedentary adults — not an optimum. For anyone active, older, dieting or training, the evidence points higher: roughly 1.2–2.2 g/kg depending on the goal, which is what the goal pills on this page encode.

Can too much protein harm my kidneys?

In healthy people, studies up to about 2.5–3 g/kg have not shown kidney harm. People with existing kidney disease are a different case and follow their clinician's limit. If that is you, this calculator is not the right tool.

Does protein timing matter — is there an anabolic window?

Total daily intake matters far more than timing. Spreading protein across 3–4 meals (roughly 0.4 g/kg per meal) squeezes out a small extra benefit for muscle building; a strict post-workout window is mostly myth.

What if I eat plant-based protein?

Plant proteins are often lower in one amino acid or another, but a varied day — grains, legumes, soy, nuts — covers them all. Many plant-based athletes aim for the top of their range to allow for slightly lower digestibility.

Does extra protein turn into fat?

Protein is converted to fat very inefficiently. What decides fat gain is total calories: protein eaten inside your calorie target does not meaningfully become fat, whatever the grams say.

Do older adults need more protein?

Yes — ageing muscle responds less to protein (anabolic resistance), so guidance for over-60s usually starts at 1.0–1.2 g/kg even without training, and higher with it. Pick at least the Active goal if you are over 60.

Privacy and important information

This calculator runs entirely in your browser: your numbers are never sent to a server, stored, or shared. Protein targets are general information for healthy adults — kidney disease, pregnancy and other medical situations need a clinician's numbers, not a web calculator's.

Part of RahaKit's free health calculators.

Protein Calculator