One Rep Max Calculator
Estimate your maximum lift without risking injury. Enter a weight you lifted and the reps to see your 1RM.
What Is a One Rep Max (1RM)?
Your one rep max is the maximum weight you can lift for a single repetition with proper form. Knowing your 1RM helps you program your training — warm-up sets, working sets, and progression are all based on percentages of your 1RM.
1RM Calculator FAQ
How accurate are 1RM calculators?
1RM formulas are accurate within 5-10% for reps under 10. For higher reps, accuracy decreases. Always treat estimates as guidelines, not exact numbers.
Which formula is most accurate?
The Epley and Brzycki formulas are the most validated. We average all four formulas for a more robust estimate.