One Rep Max Calculator
Enter a weight and the reps you completed to estimate your one-rep max and training loads.
How to use it
- Enter the weight The load you lifted, in any unit.
- Enter the reps How many clean reps you completed.
- Read your 1RM See your estimated max and a rep table.
Examples
| 100 × 5 | ~116 |
|---|---|
| 80 × 8 | ~99 |
About this tool
Your one-rep max is the most weight you can lift for a single repetition — a key reference for designing strength programs. Rather than risk an actual max attempt, this calculator estimates it from a set you’ve already done using two trusted formulas, Epley and Brzycki, and reports their average.
It also prints a table of training loads at common rep ranges, so you can turn your estimated max into practical working weights. The estimate is a guide, not medical or coaching advice; warm up properly and lift safely. Everything runs in your browser.
Frequently asked questions
Which formula is best?
Epley and Brzycki are both popular and give similar numbers for low reps. This tool averages them and shows each so you can compare.
Should I actually lift my 1RM?
Estimating is much safer than testing. Treat the number as a guide for programming, and never max out without proper warm-up and a spotter.
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Updated June 12, 2026