One-Rep Max Calculator
Example: Weight lifted: 225 lb · Reps completed: 5 reps
| Estimated one-rep max | 257.81 |
| 85% training load | 219.14 |
| 70% training load | 180.47 |
Worked example
Say you bench 225 lb for 5 clean reps. The Epley formula gives 225 x (1 + 5/30) = 262.5 lb, and Brzycki gives 225 x (36 / (37 - 5)) = 253.1 lb. Averaging the two lands on about 258 lb as your estimated one-rep max. From there, an 85% day is roughly 219 lb and a 70% volume day is about 180 lb.
Frequently asked questions
How many reps should I use for the most accurate estimate?
Estimates are most reliable in the 3 to 8 rep range taken close to failure. Above about 10 reps, small differences in endurance and form make the number drift, so a heavy set of 5 is a common sweet spot. This tool blends two formulas to smooth out the error either one carries on its own.
Why average Epley and Brzycki instead of picking one?
Epley tends to read slightly high at higher reps while Brzycki reads slightly low, so averaging them cancels part of each formula bias. The result is usually closer to a lifter true single than either estimate alone across common rep ranges.
Is it safe to attempt an actual one-rep max?
A true max attempt should only be done with a proper warm-up, good technique, and ideally a spotter or safety bars. For most people an estimated 1RM from a hard set of 3 to 5 is safer and precise enough to program training around.
How often should I retest my one-rep max?
Every 4 to 8 weeks is typical, usually at the end of a training block. Retesting too often does not give strength time to build, and the estimate will bounce around with daily fatigue and sleep.