One Rep Max Calculator
Estimated 1RM and percentage chart
Your Set
Reps to failure in one set (2–10 works best)
Estimated one rep max
260 lb
Epley262.5 lb
Brzycki253.1 lb
Lombardi264.3 lb
Percentage of 1RM
| % | Weight | Plate-rounded | Approx. reps |
|---|
Plate-rounded values use 5 lb steps (2.5 kg in metric). Approximate reps are back-calculated from the Brzycki formula.
Training Zones by Goal (NSCA)
| Goal | Intensity | Reps | Sets |
|---|---|---|---|
| Strength | 85%+ | 1–6 | 2~6 |
| Hypertrophy | 67–85% | 6–12 | 3~6 |
| Muscular endurance | ≤ 67% | 12+ | 2~3 |
Warm-up Before a 1RM Test
| Step | Load (of estimated 1RM) | Reps |
|---|---|---|
| 1 | 40~50% | 5~10 |
| 2 | 60~70% | 3~5 |
| 3 | 80% | 2~3 |
| 4 | 90% | 1 |
| 5 | 100%+ attempt | 1 |
Rest 2–4 minutes between attempts and always use a spotter or safety bars. Beginners are safer estimating 1RM than testing it.
Formulas & Sources
- Epley (1985): weight × (1 + reps ÷ 30)
- Brzycki (1993): weight × 36 ÷ (37 − reps)
- Lombardi (1989): weight × reps^0.10 · result = average of the three; a single rep is taken as-is
- Training zones: NSCA Essentials of Strength Training and Conditioning
Last reviewed: 2026-10-19
FAQ
What is a one rep max (1RM)?
Your 1RM is the heaviest weight you can lift for a single rep. Programs use it to set loads, e.g. '10 reps at 70% of 1RM'.
What is my 1RM if I bench 225 lb for 5 reps?
About 260 lb (average of three formulas): Epley 262.5 lb, Brzycki 253.1 lb, Lombardi 264.3 lb.
How many reps give the best estimate?
Sets of 2–10 reps are the most reliable. Beyond 12 reps endurance plays a bigger role and estimates drift.
What percentage should I train at for muscle growth?
Hypertrophy work is usually 67–85% of 1RM for 6–12 reps; strength work is 85%+ for 1–6 reps.
Should I test my 1RM directly?
Experienced lifters can test after a proper warm-up with a spotter or safety bars. Beginners are safer using an estimate.