How it's calculated
1RM = w × (1 + reps ÷ 30)
w = weight lifted, reps = repetitions performed. Epley formula for one-rep max.
Worked examples
| Weight | Reps | Epley 1RM | Brzycki 1RM |
|---|---|---|---|
| 185 lb | 5 | 216 lb | 208 lb |
| 225 lb | 3 | 248 lb | 238 lb |
| 135 lb | 10 | 180 lb | 180 lb |
Common questions
How accurate are 1RM estimates?
They're most accurate under about 10 reps. Beyond that, fatigue and form drift make the formulas overestimate.
Why do Epley and Brzycki differ?
They use slightly different rep formulas, so estimates diverge as reps climb. Averaging the two smooths out the difference.