Vital / Free tools / One-rep max
One-rep max estimator
Epley and Brzycki, side by side. Sets of 1 to 10 reps.
Estimate the heaviest single you could lift from a lighter set, without testing a true max. It runs in your browser and sends nothing anywhere.
Enter a weight and reps and your estimate appears here. Nothing you type leaves this page.
Estimated one-rep max
Average of the two formulas
| Share of max | Weight |
|---|
An estimate, not a promise. The share table is simple multiplication; how many reps you can do at each share varies from lifter to lifter and lift to lift.
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Join the Android betaThe two formulas
Epley: 1RM = weight x (1 + reps / 30) Brzycki: 1RM = weight x 36 / (37 - reps)
Both take a set you did and project the heaviest single. For one rep, the estimate is just the weight lifted. The calculator shows both and their average, because they disagree a little and neither is the truth.
Limits
- Both are built for lower rep counts. Past about 10 reps the estimate gets unreliable, so this calculator stops at 10. Brzycki cannot be used at 37 reps at all, because the formula divides by zero.
- They are population formulas. Your own max can sit above or below the estimate, and different lifts behave differently.
- Do not use an estimate as a reason to attempt a true max without a spotter or safety pins.
Sources
- Epley B. Poundage chart. Boyd Epley Workout. Lincoln, NE: Body Enterprises, 1985.
- Brzycki M. Strength testing: predicting a one-rep max from reps-to-fatigue. J Phys Educ Recreat Dance 1993;64(1):88-90. doi:10.1080/07303084.1993.10606684
The Vital app uses estimates like these for its personal records, limited to sets of 1 to 10 reps. See workout features.