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Strength Tools
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Strength calculator

Rep Max Calculator

Turn any hard set into an estimated X-RM for any rep range.

Rep Max Calculator

Calculate your X-RM for any target rep range

What this does

Based on a sub-maximal set you performed, this calculates the maximum weight you can lift for a specific number of reps (your X-RM).

Example Use Case

You lifted 225 lbs for 5 reps at 2 RIR. You want to know your estimated 3-RM.

  • • 5 reps at 2 RIR = 86.2% of 1RM
  • • Estimated 1RM = 225 / 0.862 ≈ 260.9 lbs
  • • 3 reps at 0 RIR = 95.2% of 1RM
  • • Estimated 3-RM = 260.9 × 0.952 ≈ 248.4 lbs