One Rep Max Calculator — estimate your 1RM and training percentages
A one rep max is the heaviest weight you can lift once with good form. You do not need to test it to use it — a hard set of five predicts it closely enough to program from.
Estimate your one rep max
- Estimated 1RM
- 91.7 kg
- Epley
- 93.3 kg
- Brzycki
- 90.0 kg
- Hypertrophy (75%)
- 68.8 kg
| Percent | Weight | Typical reps |
|---|---|---|
| 95% | 87.1 kg | 1–2 |
| 90% | 82.5 kg | 2–3 |
| 85% | 77.9 kg | 4–5 |
| 80% | 73.3 kg | 6–7 |
| 75% | 68.8 kg | 8–9 |
| 70% | 64.2 kg | 10–11 |
| 60% | 55.0 kg | 14–16 |
Results are estimates for general guidance and are not medical advice. See our medical disclaimer.
The formulas used
Epley estimates 1RM as weight × (1 + reps / 30). Brzycki uses weight × 36 / (37 − reps). Both are reliable up to about ten reps and drift apart beyond that, so this calculator shows the average of the two.
How to use the percentage table
Strength work generally lives between 80 and 92 percent for 1 to 5 reps. Hypertrophy work sits between 65 and 80 percent for 6 to 12 reps. Technique and warm-up sets sit below 60 percent.
Re-test with sets, not singles
Repeating a five-rep set every four to six weeks and recalculating is safer than maxing out, and it gives you the same information for programming.
Frequently asked questions
How accurate is a 1RM calculator?
Within a few percent when the set was taken close to failure with clean technique and eight reps or fewer.
Which formula is better, Epley or Brzycki?
They agree closely at low reps. Brzycki reads slightly lower at higher reps; averaging both is a sensible default.
Should beginners test a 1RM?
No. Estimate it from a set of five and spend the first months building technique and volume instead.