This calculator estimates your one-rep max (1RM) from a multi-rep set using the Epley formula (1RM = weight x (1 + reps / 30)), the same rule the Pelaris app uses, so one set reads the same in both. If you stopped short of failure you can add your Reps in Reserve (RIR), and it flags sets above 10 effective repetitions where linear projection error increases.
Core Equation & Guard-Rail
1RM = Weight × (1 + Reps ÷ 30) · optional: add Reps in Reserve to Reps
Reynolds, Gordon and Robergs (2006) concluded that a one-rep max can be estimated well from multiple-repetition sets, and advised staying at or under about ten repetitions. Past that, the result is a rough guide because the set measures endurance and discomfort tolerance as much as maximal strength.
Leave this at 0 RIR and the number is plain Epley on the reps you completed, the same as the Pelaris app shows for the same set. If you stopped short of failure, choose the reps you had left and they are added to the set.
116.7 kg
Epley · 5 effective reps
94.5 kg
Strength-Hypertrophy
87.5 kg
Hypertrophy Working Load
| Reps | % 1RM | 0 RIR Max | Target @ 2 RIR | Training Zone |
|---|---|---|---|---|
| 1RM | 100% | 116.5 kg | 106 kg | Max Strength |
| 2RM | 94% | 109.5 kg | 103 kg | Max Strength |
| 3RM | 91% | 106 kg | 100 kg | Max Strength |
| 5RM | 86% | 100 kg | 94.5 kg | Strength-Hypertrophy |
| 6RM | 83% | 97 kg | 92 kg | Hypertrophy |
| 8RM | 79% | 92 kg | 87.5 kg | Hypertrophy |
| 10RM | 75% | 87.5 kg | 83.5 kg | Hypertrophy |
| 12RM | 71% | 83.5 kg | 79.5 kg | Hypertrophy |
| 15RM | 67% | 78 kg | 74.5 kg | Muscular Endurance |
General fitness and training estimates only. Not medical advice.
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1RM = Weight × (1 + Reps ÷ 30) · optional: add Reps in Reserve to Reps
Reynolds, Gordon and Robergs (2006) concluded that a one-rep max can be estimated well from multiple-repetition sets, and advised staying at or under about ten repetitions. Past that, the result is a rough guide because the set measures endurance and discomfort tolerance as much as maximal strength.
General fitness and training estimates only, labelled EST. Not medical advice or a clinical diagnosis.
Verified Literature
Your projected 1RM is read off a hard multi-rep set, and this study is the evidence that a max can be estimated well without you ever having to test one.
Reynolds, J.M., Gordon, T.J. & Robergs, R.A. "Prediction of one repetition maximum strength from multiple repetition maximum testing and anthropometry." Journal of Strength and Conditioning Research, 2006;20(3):584-592. doi:10.1519/R-15304.1
View the sourceReps in reserve is how we ask you to rate a set, a scale built so your effort on the day sets the load rather than a fixed number on paper.
Helms, E.R., Cronin, J., Storey, A. & Zourdos, M.C. "Application of the Repetitions in Reserve-Based Rating of Perceived Exertion Scale for Resistance Training." Strength and Conditioning Journal, 2016;38(4):42-49. doi:10.1519/SSC.0000000000000218
View the sourceHow your loads, sets and rest periods step up across a training block follows the American College of Sports Medicine's progression model for healthy adults.
American College of Sports Medicine. "American College of Sports Medicine position stand. Progression models in resistance training for healthy adults." Medicine & Science in Sports & Exercise, 2009;41(3):687-708. doi:10.1249/MSS.0b013e3181915670. Widely cited as Ratamess, N.A. et al., 2009, after the writing group's lead author.
View the sourceDeep-Dive Training Guides
Automatic Tracking & Adaptation
Inside Pelaris, you never need to punch numbers into a spreadsheet. Every logged set, run and check-in updates your estimates automatically and adapts next week’s sessions.
Strength & Power
Deload & Readiness Calculator
Score four fatigue signals to see whether to keep progressing or deload, with suggested deload sets (-40% volume) and bar weights (85-90% load) at 3 to 4 RIR.
Strength & Power
Plyometric Contacts Calculator
Plan plyometric ground contacts per session (about 65 to 125) by athlete tier, sport focus and season phase, with 48 to 72 hours between plyometric days.
Strength & Power
Workout Split & Volume Analyser
Audit your weekly sets per muscle group, push-to-pull ratio and leg symmetry against Schoenfeld’s 10 to 20 set landmarks, or drop in a Hevy/Strong CSV.
By default it does not. The calculator uses plain Epley on the reps you completed, which is exactly what the Pelaris app does, so a set reads the same number in both. If you choose a RIR, it adds those reps to the set: a set of 5 reps stopped with 2 reps in reserve (2 RIR, or RPE 8) reflects the capacity of an all-out 7-rep set, so adding them avoids underestimating your ceiling when you stopped well short of failure.
Reynolds, Gordon and Robergs (2006) advised staying at or under about ten repetitions when predicting a one-rep max. Beyond that, a set tells you as much about endurance and discomfort tolerance as about maximal strength, so the projection is a rough guide.
Most productive strength and hypertrophy training happens at 1 to 3 RIR (RPE 7 to 9) rather than failure. The Target @ 2 RIR column shows the bar weight that leaves 2 clean reps in the tank at each rep count, so you can pick a working load for your target reps.