One Rep Max Calculator
Estimate your one-rep max (1RM) from a submaximal set, with a training percentage table.
One Rep Max (1RM) Calculator
Your Result
| % of 1RM | Weight | Typical reps |
|---|
How One Rep Max Is Estimated
This calculator uses the Epley formula, one of the most widely used methods for estimating one-rep max (1RM) from a set of multiple reps, without needing to actually attempt a maximal lift (which carries higher injury risk, especially untested).
Formula
1RM = Weight × (1 + Reps ÷ 30)
This works best for sets of 2-10 reps, estimates from very high rep sets (15+) tend to be less reliable.
Frequently Asked Questions
How accurate is an estimated 1RM?
It's a solid estimate for programming purposes, typically within a few percent of your true max for sets of 2-10 reps, but individual variation exists, especially at very high or very low rep ranges.
What is the percentage table for?
Many strength programs prescribe work at specific percentages of your 1RM (e.g. 5x5 at 80%), the table converts your estimated max into practical training weights.
Should I test my actual 1RM instead?
Testing a true 1RM carries more injury risk, especially without a spotter or coach. Estimating from a manageable submaximal set is generally safer for most lifters.