Strength
One-Rep Max Calculator
Estimate a 1RM from a hard set using the Epley formula. Use it to pick working weights, not to ego-load.
Hunter: If the last rep was ugly, do not trust the number. Clean reps only. I do not max in week one of a new lift.
Epley in plain English
Weight times (1 + reps / 30). A 225 x 5 set estimates about 262. Best used for sets of 10 or fewer. If you ground out 12 sloppy reps, this formula will lie to you in the direction your ego likes.
What I actually do with it
I take a hard, clean set of 5, run the number, then pick working weights as a slice of that estimate. I do not walk over to the bar and test a true single because a calculator felt spicy. Estimated max is for programming. Real singles are a later conversation with a coach.
First gym month
You probably do not need this yet. Goblet squats and machines need logged working sets, not a 1RM personality. When you have a barbell movement you can own for 5, then this page earns its keep. Pair it with the plate calculator so you are not doing math with wet hands.
Ugly reps void the estimate
Hips shooting up, bar bouncing off the chest, hitching a deadlift: that is not the set to plug in. Film a silent set if you need a parent to check. Then use a clean one. The Engine log of actual working sets still matters more than a theoretical max.
FAQ
Should I test a real max?
Most people do not need to. Estimated 1RM is enough to set percentages and track progress in Engine.
Is this safe for high school?
The formula is just math. Maxing out is a coaching choice. When in doubt, log working sets and skip the single.
Use the estimate to pick next week's working sets, then log those sets in the free Vitality Engine.