One-Rep Max Calculator
Estimate your 1RM from a set, with a % loading table.
Most accurate at 2-10 reps taken near failure.
Estimate · 1RM
114.6 kg
Percentage of 1RM (based on the average)
| % 1RM | Load (kg) | Typical reps |
|---|---|---|
| 100% | 115 | 1 |
| 95% | 109 | 2 |
| 90% | 103 | 4 |
| 85% | 97 | 6 |
| 80% | 92 | 8 |
| 75% | 86 | 10 |
| 70% | 80 | 12 |
| 65% | 74 | 15 |
How the one-rep max calculator works
Your one-rep max (1RM) is the most weight you can lift for a single repetition. Testing a true 1RM is risky, so most lifters estimate it from a set taken close to failure.
This tool shows two published estimates. The Epley formula (1985) is 1RM = weight x (1 + reps/30). The Brzycki formula (1993) is 1RM = weight x 36 / (37 - reps). Both are accurate for sets up to about ten reps and diverge as rep counts climb.
The percentage table below turns your estimated 1RM into working loads. It follows the standard strength-training relationship where roughly 85% of 1RM allows about 6 reps and 75% allows about 10.
- Estimates are most accurate at 2-10 reps. Above that, error grows quickly.
- Epley and Brzycki agree closely at low reps and separate as reps rise. Use them as a range, not a single true value.
- Round working weights to the nearest plate you actually have.