OneRepMax

What it is

OneRepMax is a free strength training calculator that estimates your one-rep max (1RM) from submaximal lifts. Enter the weight and reps you completed, and the calculator estimates your maximum single lift using seven published formulas: Epley, Brzycki, Lombardi, Lander, Mayhew, O'Conner, and Wathen. It shows the average of all seven formulas as the primary estimate, plus individual formula results and the range between them.

The tool includes a percentage chart that converts your 1RM into training loads from 100% down to 50%, rounded to standard plate weights in kilograms or pounds. It also provides a rep-max table showing estimated loads for lifts from 1RM through 12RM. The site covers dozens of exercises across chest (bench press variations, dips), shoulders (overhead press, push press), back (deadlift variations, rows, pull-ups), legs (squats, leg press, leg curl), arms (curls, extensions), and Olympic lifts (power clean, snatch). All data is saved locally in your browser with no account required.

Questions from the bench

What do I type into the one rep max calculator?

Type the weight you lifted and how many reps you completed, choose kilograms or pounds, and the calculator estimates a one-rep max with seven published formulas and shows the average plus a percentage chart.

Which formula should I use?

Start with the average of all seven. It does not pretend one equation is right. Bench variations default to Mayhew, conventional and sumo deadlifts default to Brzycki, and other lifts default to Epley, but you can override any of those.

Is a calculated 1RM the same as a tested max?

No. A tested max is the heaviest single you actually lift. A calculated 1RM is a guess from a submaximal set. Use it to pick training loads and test a true max only when you have a reason, a spotter or safety arms, and a setup you trust.

How many reps make a useful estimate?

Sets of about 3–6 reps usually give a tighter estimate than sets of 12 or more. The calculator runs up to 20 reps and warns above 10. Olympic lifts are the exception: keep those tests to singles or very low reps.

What does the RPE toggle do?

It adds reps in reserve before the formulas run. A set of 5 at RPE 8 is treated as 7 effective reps, because you judged that about two reps were left.