Protein Calculator
Find your daily protein target based on body weight and training goals.
Please note: For general information only. This is not medical advice — speak to a doctor or registered dietitian before changing your diet, training or medication.
What the Protein Calculator does
Protein needs scale with body weight and training. The 0.8 g/kg RDA is set to prevent deficiency in the general population, not to support muscle growth, and sports-nutrition position stands recommend more for people training hard. Exactly how much more is not settled: published ranges for building or preserving muscle vary roughly between 1.2 and 2.2 g/kg depending on the source, the training status of the people studied and whether they were in an energy deficit. The presets below span that range rather than asserting one figure.
Formula
Protein grams = Body weight (kg) × Target g/kgLean-mass basis: Lean body mass (kg) × 2.2
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| Units | one of 2 options | Yes | — |
| Weight | kg or lb | Yes | Accepts 1 or more. |
| Goal | one of 5 options | Yes | — |
| Body fat percentage | % | Optional | Optional — bases the target on lean mass instead. Accepts 1 or more, up to 70. |
How to use it
- Choose Units and Goal.
- Enter Weight.
- Optionally add Body fat percentage.
- Select Calculate.
Worked example
An 80 kg person building muscle.
- Weight
- 80 kg
- Goal
- Building muscle
80 × 1.8 = 144 g of protein a day, about 576 calories.
Frequently asked questions
Can too much protein harm the kidneys?
In people with healthy kidneys, high protein intake has not been shown to cause damage. Those with existing kidney disease should follow medical guidance.
Do I need protein immediately after training?
The "anabolic window" is far wider than once believed. Total daily intake matters much more than timing.
Method and sources
Method. Body weight multiplied by a grams-per-kilogram target the reader selects, with presets spanning the range published across dietary reference values and sports-nutrition position stands.
Assumptions
- The reader is a healthy adult with normal kidney function.
- Body weight is used as the basis. Some position stands recommend lean mass instead, which gives a materially lower figure at higher body-fat percentages.
Limitations
- How much protein supports muscle gain is not settled. Published ranges vary with training status, energy balance and how the studies measured outcomes, which is why the presets span a range rather than asserting a number.
- Population reference values such as the RDA are set to prevent deficiency across a population, not to optimise anything for an individual — reading one as a target misunderstands what it is.
- Anyone with reduced kidney function should take a protein target from their clinician, not from a calculator.
Sources
- Sports-nutrition position stands and national dietary reference values — Varies by body; the presets span the range these publish rather than following one. The span of the g/kg presets. No single source establishes the whole range, which is why none is cited as if it did.