A Brief About 1RM
To calculate the maximum amount of weight that you can lift just once (also known as your “one repetition maximum” or “1RM”) for any given type of weight lifting exercise, select a weight that you predict you can lift up to a maximum of 10 repetitions and perform a set with this chosen weight, completing as many repetitions as you can until failure (i.e. continue lifting until you can no longer lift the weight with proper form). If you exceed 10 repetitions before failure then, after resting for 10 minutes, try a heavier weight such that you fail before or at 10 repetitions. When you are finished enter the amount of weight you lifted and the number of repetitions you completed into the 1RM calculator
Note: This 1RM calculator should be treated only as a rough prediction tool, and its accuracy will vary depending on a large number of factors, one of which is the resistance training experience of the user.
Our online fitness trainers can help you in understanding this in more detail.