One-Rep Max Calculator
Estimate your one-rep maximum from a lift.
Estimated 1RM
—
Suggested warm-up (barbell)
—
| % of 1RM | Weight (kg) | Weight (lb) | Est reps* |
|---|
*Very rough reps-at-% guidance assuming non-grindy sets. Individual
response varies.
About formulas
Epley: 1RM = W × (1 + R/30). Works well 1–10 reps.
Brzycki: 1RM = W × 36/(37 − R). Often conservative at higher reps.
Use recent, well-executed sets. Very high reps (10+) tend to overestimate.
Help & FAQ — One-Rep Max Calculator
How to use
- Choose kg or lb and enter the weight lifted and reps completed.
- Choose Epley or Brzycki, then adjust plate rounding, bar weight and warm-up top set if needed.
- Review the estimated 1RM, warm-up and percentage table; copy or share the result.
Use cases
- Estimate your 1RM from a working set.
- Calculate training percentages for strength blocks.
Tips & FAQs
- Which formulas can I compare?
- Switch between Epley and Brzycki to compare estimates for the same set.
- Can I keep a result?
- Copy results or Share saves a summary for you to keep elsewhere. There is no progress-history feature.
Formats & limits
- Input reps: 1–12
- Supports metric and imperial units
- Estimates assume steady effort—actual strength varies day to day
Privacy
Calculations run in your browser. Copy places the summary on your clipboard; Share sends the displayed results through your chosen app.
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Updated
15 October 2025