One Rep Max Calculator
Jenzzy uses the Epley formula to project maximal strength from a safe working set.
Inputs
Results
Enter values to see results.
Formula
1RM = Weight × (1 + Reps/30)
Epley estimates maximum load from reps performed below failure.
Example
- Epley: 100 × (1 + 5/30)
- 1RM: ≈ 116.7 kg= 116.7 kg
Result: Estimated 1RM ≈ 116.7 kg
Frequently Asked Questions
Which formula?
Epley is common; Brzycki differs slightly at high reps.
Safe testing?
Avoid true 1RM attempts without spotters and warm-up.
High rep sets?
Estimates above ~10 reps are less reliable.