One Rep Max from Reps
Free One Rep Max from Reps calculator with clear step-by-step results.
About One Rep Max from Reps
The Epley formula estimates a one-rep max from a submaximal set.
Formula
Formula
1RM ≈ weight × (1 + reps ÷ 30)
Worked example
With the default values below, One Rep Max from Reps returns Estimated 1RM of 171.0. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Weight liftedminimum 0 lb
- 135 lb
- Reps performedaccepts 1–20
- 8
Results
- Estimated 1RM
- 171.0 lb
- Epley Formula
- 171.0 lb
- Estimated % of 1RM Used
- 78.9%
Step by step
- 1Values used
- 2Formula
- 3Estimated 1RM= 171.0 lb
- 4Epley Formula= 171.0 lb
- 5Estimated % of 1RM Used= 78.9
Assumptions and limits
- The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
- Estimates are general guidance — consult a healthcare professional for personal medical advice.
- This is an estimate for general information and not professional medical advice. See the full disclaimer for the limits that apply to this kind of calculator.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Estimates are general guidance — consult a healthcare professional for personal medical advice.
Frequently Asked Questions
How does this calculator work?
The Epley formula estimates a one-rep max from a submaximal set.
Why does this matter?
Estimate only — test 1RM safely with a spotter.