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Calculators / Health & fitness / One-repetition maximum
One-repetition maximum calculator
Estimate one-repetition maximum from a lifted weight and repetitions.
On this page
Estimated one-rep max101.33same weight unit
Calculator controls
How to calculate
Estimate one-repetition maximum from a lifted weight and repetitions.
Estimated one-rep max = weight*(1+reps/30)
Worked example
Weight lifted: 80; Repetitions: 8.
Estimated one-rep max: 101.33 same weight unit.
Assumptions and limits
The Epley estimate is most useful at moderate rep counts. Do not attempt a maximum lift without appropriate experience and supervision.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
Estimate one-repetition maximum from a lifted weight and repetitions. The displayed figures use the inputs and formula shown on this page.
When this tool is useful
Use the one-repetition maximum to compare a scenario, check an estimate, or verify a manual calculation.
Understanding your inputs
| Input | What to enter |
|---|---|
| Weight lifted | Enter a number of at least 0.000001 and no more than 1000000000000. |
| Repetitions | Enter a number of at least 1 and no more than 30. |
Frequently asked questions
What should I check before using the one-repetition maximum result?
The Epley estimate is most useful at moderate rep counts. Do not attempt a maximum lift without appropriate experience and supervision.
Is this one-repetition maximum result exact?
It is exact for the stated mathematical model and entered values. Real-world results can differ when rates, timing, fees, definitions or measurement conditions differ.