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1 rep max calculator

Estimate your one-rep max from a working set using Epley, Brzycki, and Lombardi.

Your stats

Most accurate at 1–6 reps. Above 10, estimates start to scatter — use a heavier set for a closer number.

Estimated 1RM (average)
260lb

Average of the three formulas below.

  • Epley263 lb
  • Brzycki253 lb
  • Lombardi264 lb

Training percentages of estimated 1RM

  • 1 reps
    260 lb
    100 %
  • 2 reps
    247 lb
    95 %
  • 3 reps
    242 lb
    93 %
  • 4 reps
    234 lb
    90 %
  • 5 reps
    226 lb
    87 %
  • 6 reps
    221 lb
    85 %
  • 8 reps
    208 lb
    80 %
  • 10 reps
    195 lb
    75 %
  • 12 reps
    182 lb
    70 %
  • 15 reps
    169 lb
    65 %

Why estimate instead of test

Testing a true 1RM is fatiguing and slightly risky, especially outside a planned peaking block. For day-to-day programming, an estimate from a heavy set of 1–6 reps is almost as accurate and much easier to recover from. The three formulas below are the most widely used.

The formulas

Epley:    1RM = weight × (1 + reps / 30)
Brzycki:  1RM = weight × 36 / (37 − reps)
Lombardi: 1RM = weight × reps^0.1

The percentage table beneath the result follows the standard Prilepin-style mapping used in most strength programmes.

Frequently asked questions

How accurate is an estimated 1RM?
Within about 5 % when the set used to estimate it is between 1 and 6 reps and taken close to failure. Estimates from 8-rep sets are still useful; estimates from 12-rep or higher sets can drift 10 % or more depending on the formula and the lifter.
Why three formulas instead of one?
They were all developed from different data sets and produce slightly different numbers. Epley and Brzycki agree closely under 8 reps and diverge above. Lombardi runs lower at low reps and higher at high reps. Averaging them gives a reasonable middle estimate.
Should I actually test my 1RM?
Rarely. Testing a true 1RM is fatiguing, slightly risky, and unnecessary for most lifters. Estimating from a heavy set of 3–5 is almost as accurate and much kinder to your recovery. Save real 1RM attempts for meets or specific peaking blocks.
How do I use the percentage table?
It maps your estimated 1RM to the working weight at common rep ranges. For example, 5×5 typically lands around 85 % of 1RM, and 3×3 around 90 %. Use it to plan progression — but always adjust based on how the bar actually feels on the day.

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