🏋️ Epley & Brzycki formulas
One-Rep-Max Calculator
Estimate your one-rep max from any weight/reps set, then see a full percentage-based training table. Two standard formulas shown side by side. Nothing leaves your browser.
Training percentages (Epley estimate)
| % of 1RM | Weight | Typical reps |
|---|
How it works
Your 1RM is estimated two ways from a single weight/reps entry: Epley's weight × (1 + reps/30), and Brzycki's weight × 36 ÷ (37 − reps). The percentage table below then scales the Epley estimate down to standard training percentages (60-100%) alongside the rep ranges strength programs typically pair with each one.
FAQ
- Why do Epley and Brzycki give different numbers?
- They're separate curve-fit formulas derived from different rep-max data, so they don't always agree - Epley tends to run slightly higher at higher rep counts, which is why both are shown side by side instead of averaged into one number.
- Why does the Brzycki estimate show a dash at high rep counts?
- The Brzycki formula divides by (37 minus reps), so at 37 reps or more it would divide by zero or go negative - the calculator blanks the result instead of showing a nonsense number.
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