Estimate your 1RM for any lift from a submaximal set. Enter the weight and reps completed.
Frequently Asked Questions
A one rep max (1RM) is the maximum amount of weight you can lift for a single repetition with proper form. It is used as a benchmark for strength and to program training percentages. Testing a true 1RM carries injury risk, so estimating it from submaximal sets is safer.
The Epley and Brzycki formulas are the most widely used and validated. They are most accurate when using sets of 10 reps or fewer. As reps increase beyond 10, all formulas become less accurate because they assume a linear relationship that breaks down at higher rep ranges.
Training percentages are commonly based on 1RM. For strength: work at 85-100% of 1RM for 1-5 reps. For hypertrophy: 65-85% for 6-12 reps. For endurance: 50-65% for 12-20+ reps. Many programs like 5/3/1, Starting Strength, and nSuns are based on 1RM percentages.
Testing a true 1RM should be done infrequently — every 8-12 weeks for intermediate lifters. Frequent maximal attempts increase injury risk and CNS fatigue. Instead, estimate your 1RM from your working sets regularly and test only when peaking for a competition or milestone.
Estimated 1RM can differ from actual 1RM due to individual strength curves, fatigue tolerance, technique efficiency, and neural factors. Some lifters are better at grinding heavy singles while others excel at higher reps. The estimate is most accurate at lower rep ranges (3-5 reps).