Free Tool

One-Rep Max Calculator

Estimate your 1RM from any rep range, and see training percentages to set accurate loads.

Weight lifted
Most accurate at 12 reps or fewer.
Your Estimated 1RM
One-rep max

Training Percentages
90%
80%
70%
60%

Enter a weight and rep count above to see your estimated max.

How to read this

  • This estimates your max from a set you've actually completed, not from testing a true one-rep max.
  • It's most accurate for sets of 12 reps or fewer, and less reliable much beyond that.
  • Use the percentages to set training loads across a week, not as a one-off max attempt.
  • This is a general estimate, not a substitute for testing under proper supervision if you want an exact number.