One Rep Max Calculator

Fill out the information below to find out your one rep max (1RM).

Weight Lifted

Lbs or Kg

Number of Reps



Here are your results based on the information you’ve provided.

Want to learn more about 1RM and what it’s used for? Click here for more information
If you want to learn more about the reliability of the 1RM, check out this study.

What is One Rep Max and How it Works

A 1RM is the potential maximum weight you can lift for at least one repetition. Plenty of workout programs base exercise weight based upon this. For example, a program can say like “Do Squats 3 sets of 5 reps (3 x 5) at 85% of your 1RM”. You would take your 1RM and multiply it by 0.85 and you’ll be given the amount of weight you should be lifting.