A protein estimate has two parts: body weight in kilograms and a suitable grams-per-kilogram reference. Multiplication is simple; choosing the right reference depends on the person. A calculator’s output is a planning estimate, not a diagnosis or individualized nutrition prescription.
Convert weight before multiplying
Kilograms = pounds ÷ 2.20462. A person weighing 154 lb is approximately 69.85 kg. Entering 154 as kilograms would more than double the calculated result. Our updated protein intake calculator accepts kilograms or pounds and converts the weight when you switch units. Select the correct unit before entering a new weight.
Understand the reference you are using
The adult Dietary Reference Intake uses 0.8 g/kg as the protein RDA reference. It is not a universal sports target. The National Academies reference tables explain the reference values and population categories.
For athletes, the NIH Office of Dietary Supplements summarizes commonly recommended daily intakes of about 1.2–2.0 g/kg. Training, total energy intake and individual circumstances affect the appropriate target. More protein does not automatically produce more muscle.
Worked examples for a 70 kg adult
- At 0.8 g/kg: 70 × 0.8 = 56 g/day.
- At 1.2 g/kg: 70 × 1.2 = 84 g/day.
- At 2.0 g/kg: 70 × 2.0 = 140 g/day.
These calculations illustrate different references; they do not mean every 70 kg adult needs 140 g. Select the adult, athletic or custom reference explicitly. The custom option converts your own supplied target into daily grams; it does not assess or endorse that target.
Translate a daily number into a practical food check
Use food labels or a reliable food-composition source to total the portions you actually eat. Be consistent about cooked versus raw weights and serving sizes. For an arithmetic example, four meals containing 25 g each total 100 g. That is a counting example, not a requirement to eat four meals or exactly 25 g at each.
Protein foods also supply other nutrients, and the overall diet matters. A supplement is not automatically required to reach an intake target.
When a generic calculator is not enough
Children, pregnancy, breastfeeding, kidney disease and other medical circumstances need guidance appropriate to that situation. If you have been given a clinician’s or registered dietitian’s target, use that advice rather than replacing it with a generic goal setting.
Use the calculator to understand units and arithmetic, then assess whether its selected assumptions fit your circumstances. It cannot assess medical history, dietary adequacy or a safe individual treatment plan.
Content reviewed on 9 October 2026. Worked examples are hypothetical. The original article URL is retained.