Enter any weight and rep count — no need to actually max out to know roughly where you stand.
| % of 1RM | Weight | Typical Use |
|---|
Enter a weight you lifted and the number of clean reps you completed, and the page estimates your one-rep maximum plus a table of working weights at each percentage. Reps must be honest: a set that stopped because of form rather than fatigue is not a set to five.
The estimate is most reliable between about three and eight reps. Above ten, the formulas drift; below three, a single rep is noisy enough that you may as well test it under supervision.
185 lb for 5 reps:
| Formula | Estimate |
|---|---|
| Epley: weight × (1 + reps ÷ 30) | 215.8 lb |
| Brzycki: weight × 36 ÷ (37 − reps) | 208.1 lb |
| Average used here | 212 lb |
From that 212 lb the working weights follow directly: 90% is 191 lb, 85% is 180 lb, 80% is 170 lb, and 70% is 148 lb. Those are the numbers a percentage-based programme asks for, and they are why the estimate is useful even if it is a few pounds off — a 3% error moves the 80% set by five pounds, which is one plate change.
Two formulas are averaged because they disagree in a predictable direction: Epley overestimates as reps climb, Brzycki underestimates at low reps. Their average is a reasonable middle, and neither is a measurement. The only true one-rep maximum is a single rep you actually complete with acceptable form.
Use the table for programming, not for bragging. A 5×5 programme at 80% means five sets of five at 170 lb, which is a genuinely hard session. If 170 feels like a warm-up, your true max is higher than 212 and the rep count you entered was too low.
Fatigue, sleep, caffeine and how recently you trained all move a single-day estimate. Test again in a few weeks rather than treating one number as a permanent fact about your strength. And for anyone new to lifting, the estimates will run high, because the formulas were built on trained lifters.
Usually within a few percent for sets of three to eight reps. It gets less reliable at high reps and for people with little training experience.
Only with a spotter and after a proper warm-up, and not often. Most programmes run fine off an estimate from a solid set.
They were fitted to different data. Neither is wrong; the average is a hedge that behaves reasonably across the rep range.
Around 70–85% for strength work, 60–75% for volume. The table gives the weights; the programme decides the sets.
Not to the formula. A 212 lb bench press means the same thing at any bodyweight, though what it means relative to you does not.
Epley and Brzycki are gym equations from the late 1980s and early 1990s. They are not a medical standard, and there is no single federal page that blesses either one. The training context is general fitness guidance, not a strength certificate.
Last updated: November 2, 2026. Reviewed by David Liu.