One-Rep Max & Percentage Calculator
Estimate your one-rep max (1RM) from any weight and rep count, then read off a full training-percentage table and barbell plate loading. Free calculator for strength and hybrid athletes — Epley, Brzycki and more.
Enter a weight and the number of reps you completed to estimate your one-rep max (1RM). The calculator averages five published formulas — Epley, Brzycki, Lombardi, O’Conner and Lander — and builds a full training-percentage table rounded to plates you can actually load on the bar.
Example: percentages of a 100 kg one-rep max
| % of 1RM | Weight (kg) | Approx. reps |
|---|---|---|
| 100% | 100 | 1 |
| 95% | 95 | 2 |
| 90% | 90 | 4 |
| 85% | 85 | 6 |
| 80% | 80 | 8 |
| 75% | 75 | 10 |
| 70% | 70 | 12 |
| 65% | 65 | 16 |
| 60% | 60 | 20 |
| 55% | 55 | 24 |
| 50% | 50 | 30 |
How accurate is a 1RM estimate?
1RM formulas are regressions fitted to real lifters and are most accurate at five reps or fewer. Above ten reps the estimate drifts, so use the number as a programming guide rather than a guaranteed max, and verify heavy singles under a spotter.