Protein per day:
weight x grams per kg

How much protein do you need per day?

Multiply your weight in kilograms by a protein factor in grams per kilogram. A 70 kg person using 1.2 g/kg needs 84 g a day. The calculator accepts factors from 0.6 to 3, with 1.2 as its default. This is an estimate, not medical advice.

A commonly quoted minimum for healthy adults is 0.8 g per kg, and higher factors are often used by people who train, but the right value depends on you.

Because the factor is a slider in 0.1 steps, you can test several values quickly: 1.0, 1.2 and 1.6 g/kg for a 70 kg person give 70, 84 and 112 g a day.

The protein formula and a worked example

The formula is a plain multiplication, so changing either input scales the result in direct proportion. A 10 per cent heavier person at the same factor needs 10 per cent more protein.

How the factor changes the target

Going from 0.8 to 1.6 g/kg doubles the target, so the factor you choose matters more than small changes in weight.

Choose the factor first, then the weight. If you are unsure, start near the default of 1.2 and ask a professional before moving to the extremes of the slider.

Splitting your target across meals

A daily number is hard to use at the table. Divide it by the meals you eat: 84 g over 3 meals is 28 g each, over 4 meals it is 21 g. Plan each meal with one clear protein source, then add snacks if you need a little more.

Eating most of the target in one meal is not necessary; a steady spread is easier to plan.

If your target feels hard to reach, check where the grams come from over a typical day. Many people are surprised to find that breakfast has very little protein, which is the easiest meal to improve.

Which weight should you use?

Use your current body weight in kilograms for a simple estimate. If you are far above or below a typical weight for your height, a dietitian can advise which value suits you. The calculator itself does not adjust for body composition.

Weigh yourself in the morning on a consistent scale and use the average of a few days. A one-off reading is less reliable than a weekly pattern.

Common mistakes with protein targets

• Entering pounds instead of kilograms.
• Picking a very high factor because more sounds better.
• Counting supplements and forgetting protein already in grains and dairy.
• Ignoring medical conditions. People with kidney disease or other conditions should follow their doctor's advice, not a calculator.

Treat the target as a daily average, not a strict limit. A day a little above or below it is no cause for concern.