One Rep Max (1RM) Calculator
Estimate your one-rep max for any lift using the Epley formula based on the weight and reps you can perform.
lbs
Estimated 1RM
216 lbs
90% 1RM194 lbs
80% 1RM173 lbs
70% 1RM151 lbs
Estimated 1RM vs Weight Lifted
How One Rep Max Is Estimated
The Epley formula estimates the maximum weight you can lift for a single repetition.
Formula
1RM = Weight x (1 + Reps / 30)
This formula is most accurate for rep ranges of 2-10. For higher reps, accuracy decreases because muscular endurance becomes a larger factor.
Why 1RM Matters
Knowing your 1RM allows you to program training at specific percentages, ensuring appropriate intensity for strength, hypertrophy, or endurance goals.
Example Calculation
You bench press 185 lbs for 5 reps.
- 011RM = 185 * (1 + 5/30)
- 021RM = 185 * 1.1667
- 031RM = 215.8, rounded to 216 lbs
- 0490% = 216 * 0.9 = 194 lbs
- 0580% = 216 * 0.8 = 173 lbs
Frequently Asked Questions
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