Protein Calculator
Last updated: June 2026 · Free · No sign-up required
Enter values above and click Calculate to see your result instantly.
Quick reference
Protein targets by goal:
| Goal / activity | Grams per lb | Grams per kg |
|---|---|---|
| Sedentary (RDA) | 0.36 | 0.8 |
| Active / general fitness | 0.5–0.7 | 1.1–1.5 |
| Building muscle | 0.7–1.0 | 1.6–2.2 |
| Cutting (preserve muscle) | 0.9–1.1 | 2.0–2.4 |
monitor_weight A starting point, not a diagnosis
This calculator gives you the same number a clinician would compute by hand from your inputs. It is informational, never a substitute for a doctor. If a result surprises you, write it down and discuss it at your next appointment — that conversation is the goal, not a verdict from a webpage.
science Built from peer-reviewed formulas
Every health calculator on CalcaTools uses an equation from the WHO, NIH, ACOG, CDC, or a published peer-reviewed paper. The exact citation is in the "Formula & methodology" section. We re-check sources quarterly and update the page when guidance changes — the "Last reviewed" date is at the top.
volunteer_activism Designed for real people
Health calculations only help if you can actually use them. We use plain-English labels (no jargon), accept both metric and US units, and show what a "normal" range looks like alongside your result — so you understand what the number means, not just what it is.
lock Private by design
Your weight, height, age, pregnancy details, and any other health input never leave your browser. Calculations run client-side; nothing is logged or stored on our side. We don't want your medical data — we just want the formula to work for you.
Interpretation guide
Protein basics:
| Concept | Detail |
|---|---|
| Per meal | ~20–40 g for muscle synthesis |
| Timing | Spread across the day |
| Quality | Complete proteins have all amino acids |
| 1 g protein | 4 calories |
Formula & methodology
Formula: Daily protein (g) = body weight (lb) x target factor (0.36 to 1.0 by goal)
Protein needs scale with body weight and activity. The sedentary RDA is about 0.36 g per pound (0.8 g/kg), but active people and those building or preserving muscle benefit from substantially more — commonly 0.7–1.0 g per pound. The calculator multiplies your weight by a goal-based factor and can divide the total into per-meal targets. Spreading intake across meals (20–40 g each) best supports muscle protein synthesis.