Key facts
- The standard benchmark for maximal strength.
- Used to program training as a percentage of your max.
- Can be estimated from a multi-rep set instead of tested directly.
- The Brzycki formula is a common estimation method.
Your 1RM is the clearest single measure of how strong you are on a given lift. Because strength programs prescribe loads as a percentage of your max (for example, 5 reps at 80%), knowing your 1RM lets you train at the right intensity instead of guessing.
Testing a true 1RM is fatiguing and, for beginners, risky. Instead, most lifters estimate it from a set they can already perform. The Brzycki formula — 1RM = weight / (1.0278 − 0.0278 × reps) — predicts your max from the weight and reps of a submaximal set, and is most accurate for sets of one to ten reps.
Use your estimated max to set working weights: strength work typically sits at 85–95% of 1RM for low reps, while hypertrophy training lives around 67–80% for moderate reps.
Frequently asked questions
How do you calculate one-rep max without testing it?
Use a rep-max formula like Brzycki: 1RM = weight / (1.0278 − 0.0278 × reps). Enter the weight and reps of a set you completed to estimate your max without lifting a true single.
How often should I test or re-estimate my 1RM?
Every 4–8 weeks is typical. Re-estimating from your working sets as your training weights climb keeps your percentages accurate without a dedicated max test.
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