e1RM guide

Epley vs Brzycki 1RM Formula

By e1RM Team · Last updated 2026-05-14

Compare the Epley and Brzycki 1RM formulas, see why their estimates differ, and learn when to use the conservative or aggressive number.

The short version

Epley usually gives a slightly more aggressive estimate as reps rise. Brzycki is often more conservative in the common 4-10 rep range. Neither is universally correct because lifters differ in fiber type, technique efficiency, and tolerance for rep work.

When Epley works well

Use Epley when you want a practical training estimate from normal strength work. It is simple, stable, and widely used in strength programming.

It is especially useful when the set was heavy enough to reflect max strength but not so heavy that one missed groove changed the entire result.

When Brzycki is the better default

Use Brzycki when you want to avoid overshooting. This is helpful for lifters starting a new block, managing joint irritation, or estimating lifts where fatigue changes technique quickly.

Compare both before loading a block

If Epley says 265 and Brzycki says 255, the gap is information. Starting a cycle from 255 may let you complete more high-quality work, while 265 may be more relevant for peaking or testing.

Who writes this

e1RM is built by an indie developer who lifts. The math behind every calculator is double-checked against original source papers (Epley, Brzycki, Lombardi, etc.). Training percentages and intensity recommendations are pulled from standard intermediate barbell programs (5/3/1, nSuns, Texas Method, GZCL) rather than invented. Have a correction or a feature request? Email feedback@e1rm.com.