Lifting heavy to failure is dangerous. Use our calculator to safely estimate your 1RM based on sets of higher repetitions.
Testing a true one-rep max places enormous stress on your central nervous system (CNS) and your joints. For novice and intermediate lifters, form often breaks down at maximal loads, significantly increasing the risk of injury.
Using a calculator allows you to track progress safely. If you can bench press 225lbs for 5 reps today, and 225lbs for 6 reps next week, your theoretical 1RM has gone up, without you ever having to risk being crushed by a heavier bar.
We use an average of two of the most proven formulas in sports science:
1RM = Weight × (1 + (Reps / 30))
This is widely considered the most accurate formula for heavy compound lifts like the Squat and Deadlift.
1RM = Weight / (1.0278 - (0.0278 × Reps))
Another classic formula, slightly more conservative than Epley.
Knowing your 1RM allows you to follow percentage-based programs (like Wendler 5/3/1). Common training zones include:
