One-Rep Max (1RM) Calculator
By Santaji GadepatilinUpdated October 27, 2026
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Type in any field to change it. Press × on a value to calculate that field instead.
How to use this calculator
Enter the weight and the number of reps you completed with good form. Your estimated 1RM and common training weights are calculated.
Formula (Epley)
1RM = weight × (1 + reps ÷ 30)
Example
80 kg for 6 reps: 1RM = 80 × 1.2 = 96 kg
Training percentages
| % of 1RM | Typical reps |
|---|---|
| 95% | 2 |
| 90% | 3–4 |
| 85% | 5–6 |
| 80% | 7–8 |
| 75% | 9–10 |
| 70% | 11–12 |
Frequently asked questions
How is one-rep max estimated?
This uses the Epley formula, 1RM = weight × (1 + reps ÷ 30). It is most accurate for sets of 2–10 reps.
Is it safe to test a true 1RM?
Maximal lifts carry injury risk. Estimating from a submaximal set is safer, especially for beginners. Always use a spotter.
What percentage for strength vs hypertrophy?
Roughly 80–90% of 1RM for strength (3–6 reps) and 65–80% for muscle growth (6–12 reps).