One Rep Max Calculator

Calculate your one-rep max (1RM) for any lift using weight and reps performed.

Result

Fill in the fields above, then press Calculate.

A one-rep max calculator estimates the maximum weight you can lift for a single repetition based on the weight and reps of a submaximal set.

Enter the weight you lifted and the number of repetitions you completed. The calculator estimates your one-rep max using four proven formulas (Brzycki, Epley, Lander, Lombardi) and provides a percentage-based training chart.

Examples

Bench press 185 lbs x 5 reps

Brzycki: 185 x 36/32 = 208 lbs. Epley: 185 x (1 + 5/30) = 216 lbs. Average estimated 1RM: approximately 210 lbs.

Frequently Asked Questions

Which formula is most accurate?
Brzycki and Epley are the most widely validated. All formulas are most accurate in the 1-10 rep range. Above 10 reps, accuracy decreases. The average of multiple formulas gives the best estimate.
How should I use the percentage chart?
Use it to plan your training weights. For strength: work at 80-95% for 1-6 reps. For hypertrophy: 65-80% for 8-12 reps. For endurance: 50-65% for 15+ reps.
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Quick Tips

  • •Test with a weight you can lift for 3-5 reps for the most accurate estimate.
  • •Retest your 1RM estimate every 4-6 weeks to keep your training percentages current.
  • •Track progress over weeks, not days — strength changes slowly.