Estimate your one-rep max without testing it. Plug in any working set — weight, reps and RPE (or RIR) — and get an e1RM you can program against. Built on the Helms/Zourdos RPE chart and the Epley, Brzycki and Lombardi families of formulas.
The most balanced and widely used formula in strength training. Delivers excellent accuracy in the 3-8 rep range and is the default used by most federations and apps.
1RM = weight × (1 + reps/30)
Best for: Squat, bench press, deadlift
View reference0 = no effort, 10 = maximum effort (RPE 10 = 0 RIR, RPE 8 = 2 RIR). Half-point increments allowed.
Enter your numbers in the calculator to see recommended working weights for every effort level
Calculate your 1RM first to see the working-weight table
Percentage of 1RM based on reps performed and rate of perceived exertion (RPE) or reps in reserve (RIR)
| Reps | RPE 10 RIR 0 | RPE 9.5 RIR 0.5 | RPE 9 RIR 1 | RPE 8.5 RIR 1.5 | RPE 8 RIR 2 | RPE 7.5 RIR 2.5 | RPE 7 RIR 3 | RPE 6.5 RIR 3.5 | RPE 6 RIR 4 | RPE 5.5 RIR 4.5 | RPE 5 RIR 5 | RPE 4.5 RIR 5.5 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 97% | 94% | 91% | 88% | 85% | 82% | 79% | 76% | 74% | 71% | 68% | 65% |
| 2 | 94% | 91% | 88% | 85% | 83% | 80% | 77% | 74% | 71% | 68% | 66% | 63% |
| 3 | 91% | 88% | 85% | 83% | 80% | 77% | 75% | 72% | 69% | 66% | 64% | 61% |
| 4 | 88% | 86% | 83% | 80% | 78% | 75% | 72% | 70% | 67% | 64% | 62% | 59% |
| 5 | 86% | 83% | 81% | 78% | 75% | 73% | 70% | 68% | 65% | 63% | 60% | 57% |
| 6 | 83% | 81% | 78% | 76% | 73% | 71% | 68% | 66% | 63% | 61% | 58% | 56% |
| 7 | 81% | 79% | 76% | 74% | 71% | 69% | 66% | 64% | 62% | 59% | 57% | 54% |
| 8 | 79% | 77% | 74% | 72% | 69% | 67% | 65% | 62% | 60% | 58% | 55% | 53% |
| 9 | 77% | 75% | 72% | 70% | 68% | 65% | 63% | 61% | 58% | 56% | 54% | 52% |
| 10 | 75% | 73% | 71% | 68% | 66% | 64% | 61% | 59% | 57% | 55% | 53% | 50% |
| 11 | 73% | 71% | 69% | 67% | 64% | 62% | 60% | 58% | 56% | 53% | 51% | 49% |
| 12 | 71% | 69% | 67% | 65% | 63% | 61% | 59% | 56% | 54% | 52% | 50% | 48% |
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