What this calculator tells you
A submaximal set can estimate maximal strength without requiring a true all-out single. The estimate is most useful when the set was technically sound and reasonably close to your limit.
How to use the One-Rep Max Calculator
- 1
Enter the load and completed repetitions from a clean set.
- 2
Keep inputs between 1 and 12 repetitions.
- 3
Use the estimate conservatively for future loading.
Formula and interpretation
Method
Epley: load × (1 + reps ÷ 30). Brzycki: load × 36 ÷ (37 − reps). This tool shows both and their average.
How to read the result
Use the estimate to choose training percentages and compare the same lift over time. Round down when safety or technique is uncertain.
Important limitations
Accuracy falls as repetitions rise and differs by exercise and athlete. Do not use a forced, painful, or technically poor set as the input.
One-Rep Max Calculator questions
Which 1RM formula is best?
No equation wins for every person and lift. Seeing two common estimates makes the uncertainty visible.
Should beginners test a true 1RM?
Usually there is no need. A controlled multi-repetition set can guide training with less technical and fatigue demand.
