Protein Calculator

Built by Puja Matharu, Australian Certified Nutritionist Updated 2026-07-30 Free, and nothing you enter leaves your browser

How this is calculated

Protein needs scale with body weight, so this calculator multiplies your weight in kilograms by a grams-per-kilogram figure appropriate to your situation. There's no single correct number — the right target depends on whether you're avoiding deficiency or optimising body composition.

Option	g per kg	Source
Minimum RDI, woman 19–70	0.75	NHMRC Nutrient Reference Values
Minimum RDI, man 19–70	0.84	NHMRC Nutrient Reference Values
Adult over 70	0.94–1.07	NHMRC — requirements rise with age
Active adult, general health	1.2–1.6	ISSN position stand
Losing weight	1.6–2.0	Evidence for lean mass preservation in a deficit
Building muscle	1.6–2.2	Morton et al. meta-analysis

Above roughly 2.2 g/kg there is little additional benefit for most people, so the ranges stop there rather than continuing upward.

Which weight should you enter?

Your current weight, in most cases. The exception is if you're carrying a significant amount of excess weight — protein requirements scale with lean mass rather than total mass, so calculating 2 g/kg from a starting weight of 140 kg produces a target that's both unnecessary and difficult to eat. In that case enter a realistic goal weight instead.

Why the per-meal number matters

The calculator splits your daily target across four meals, because distribution affects the outcome and not just the total. Most Australians eat very little protein at breakfast and a large amount at dinner. Evening that curve out — particularly getting 25–30 g at breakfast — improves both muscle retention and appetite control across the day.

Our full protein guide covers the food sources, plant-based targets and the evidence behind these ranges in more detail.

If you have kidney disease, liver disease, or you're following a protein-restricted diet for any medical reason, this calculator does not apply to you. Your target should be set by your treating team.

Frequently asked questions

How does this protein calculator work?

It multiplies your body weight in kilograms by a grams-per-kilogram figure appropriate to your situation: 0.75 to 0.84 g/kg for the Australian NHMRC minimum RDI, 1.2 to 1.6 g/kg for active adults, 1.6 to 2.0 g/kg when losing weight, and 1.6 to 2.2 g/kg when building muscle.

Should I use my current weight or goal weight?

Current weight in most cases. If you are carrying a significant amount of excess weight, use a realistic goal weight instead — protein requirements scale with lean mass rather than total mass, so a high multiplier applied to a very high starting weight produces an unnecessarily large target.

Is this calculator free?

Yes, and it requires no sign-up. All calculation happens in your browser — nothing you enter is sent to us or stored.

References

A number is a starting point, not a plan

Our AI nutritionist takes your targets and turns them into meals you'll actually eat — and adjusts as your goals, training and life change.

Try it free Book a consultation

General nutrition information only — not medical advice, diagnosis or treatment. See our health disclaimer.