One Rep Max Calculator
Estimate one-rep max (1RM) from weight lifted and reps completed.
Inputs
Results
Estimated 1RM
215.83
90% Training Load
194.25
80% Training Load
172.67
Tips
Try multiple scenarios to compare outcomes before making decisions.
Facts
Small changes in rates, percentages, or timelines can have a large compounding effect.
Notes
Results are educational estimates and may differ from official statements.
How this calculator works
- One Rep Max Calculator uses your inputs and standard math formulas to compute the results instantly.
- Edit any field to see updated values right away and compare scenarios.
- Use these estimates for planning, then confirm final numbers with your lender, employer, or provider when needed.
Last updated: February 2026. See our methodology and editorial policy.
Worked Example
Example using the current inputs:
Inputs
- Weight Lifted: 185
- Repetitions: 5
Outputs
- Estimated 1RM: 215.83
- 90% Training Load: 194.25
- 80% Training Load: 172.67
Assumptions and Limitations
- Results are educational estimates and may differ from official statements.
- Results are estimates and should be validated for high-stakes decisions.
- Inputs are interpreted using standard units and rounding rules for readability.
FAQ
How accurate is this one rep max calculator?
It follows standard formulas and provides practical estimates for quick planning.
Can I use this on mobile?
Yes. The calculator is optimized for mobile, tablet, and desktop use.
Are my values saved?
Inputs are stored locally in your browser to improve convenience on return visits.
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