One-Rep Max (1RM) Calculator
Enter the weight you lifted and how many reps you completed to estimate your one-rep max.
One-Rep Max (1RM) Calculator
Estimate your one-rep max (1RM) for a lift from the weight and reps you completed, using the Epley formula.
This is an estimate for general informational purposes only and is not a substitute for supervised strength testing. Estimates become less reliable above about 10-12 reps.
A one-rep max (1RM) is the maximum weight you can lift for a single repetition. Rather than testing it directly (which carries injury risk), the Epley formula estimates 1RM from a lighter set taken to or near failure for multiple reps.
Example
- With the default values shown above, this calculator returns: Estimated One-Rep Max ≈ 171.0.
Frequently Asked Questions
What is the Epley formula?
It estimates one-rep max as weight × (1 + reps ÷ 30) — one of several widely used formulas for estimating 1RM from a submaximal set.
How accurate is this estimate?
It is reasonably accurate for sets of about 10 reps or fewer taken close to failure, but becomes less reliable for higher rep counts or sets that are not near failure.