LiftMath guide

How to Calculate Your 1 Rep Max

A practical guide to estimating max strength without testing a true max.

Use a set that reflects strength, not survival

The best 1RM estimate usually comes from a hard but clean set of 2-8 reps. A sloppy set of 12 can make the calculator look impressive while giving you a training max that is too heavy for repeatable work.

Choose a recent set where bar path, depth, pause style, and lockout matched the way you normally train the lift. If form changed rep to rep, use a more conservative estimate.

Pick a formula and stay consistent

Epley is a good default for general barbell training. Brzycki often lands slightly lower, which can be useful when you are returning from a break or planning a high-volume block.

The exact formula matters less than consistency. If you switch formulas every week, you are tracking formula noise instead of strength progress.

Turn the estimate into training loads

Use the percentage table as a starting point, then round to plates you can actually load. For most lifters, a training max 5-10% below an all-out estimated max is easier to progress than chasing the biggest number the calculator can produce.

Retest without maxing out

Retest with another submaximal set after a few weeks. A clean 225 x 6 replacing 225 x 5 is better evidence than a rushed single after a high-fatigue block.