Nutrition & Food
Basic

Protein Requirement (RDA)

Recommended daily protein for a healthy adult (grams).

Formula

P=0.8×mP = 0.8 \times m

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Variables

mBody mass (kg)

Example

70 kg ⇒ 56 g/day

How it works

This formula estimates the recommended minimum daily protein intake for a generally healthy adult by scaling protein needs to body mass. The factor 0.8 grams per kilogram comes from nutrition guidelines that reflect the amount needed to maintain body tissues, enzymes, hormones, and muscle under typical conditions. It is a guideline, not a target for everyone: needs can be higher during growth, illness, pregnancy, intense training, or recovery.

When to use it

Use this when you want a quick estimate of a healthy adult's daily protein requirement in grams. It is helpful for meal planning, comparing food intake to nutrition guidelines, or checking whether a diet roughly meets the RDA.

Worked example, step by step

Step 1: Write the formula: P = 0.8 × m Step 2: Substitute the body mass: P = 0.8 × 62 Step 3: Calculate: P = 49.6 Step 4: Round appropriately: P ≈ 50 g/day

Common mistakes to avoid

  • Using pounds instead of kilograms without converting first
  • Treating the result as a maximum instead of a minimum guideline
  • Forgetting that this is for generally healthy adults and may not apply to athletes, children, or people with special medical needs

Did You Know?

Athletes and older adults often aim for 1.2–2.0 g/kg — well above the baseline RDA — to preserve muscle.

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Reviewed & maintained by the FormulaWon editorial teamLast reviewed September 2026