Determining Your 1 Rep Max

After you’ve established a solid exercise routine, you may want to take your strength training to the next level. You may feel that the weight you’ve been using isn’t making you work so hard anymore, and you may start wondering about your upper limits, and just how much weight you can lift. This is when your 1 Rep Max comes into play. Your 1 Rep Max (1 RM), short for One Repetition Maximum, is the heaviest weight that you can perform a certain exercise for just one successful repetition. If it was even 1 pound heavier, you would not be able to complete that full rep.

Purpose

You can use your one rep max for the purpose of testing your boundaries and limits. Knowing the most weight you can lift can help you move past milestones and serve as positive motivation work to increase that limit. Aside from that, your 1 Rep Max is great resource to work through safe progression of an exercise. When increasing and building your strength training program, it is incredibly useful to know what weight level and number of reps to move up to next.

Calculation

While it is possible to find your 1 RM simply by trial and error, it can be time consuming, difficult, and potentially dangerous. To make things easier, calculations have been developed to estimate your 1 Rep Max, using your current level as a starting ground. The table below, used along with the 1RM formula, can help you determine your 1 Rep Max.

1 Rep Max  -  Table

REPS - % 1 RM

1 - 100
2 - 95
3 - 93
4 - 90
5 - 87
6 - 85
7 - 83
8 - 80
9 - 77
10 - 75
11 - 70
12 - 67
15 - 65

To find your 1 RM for a particular exercise, you would first perform that exercise at a decently heavy weight that you’re comfortable with, for as many reps as you can. You would then plug that number of reps into the table to see what percentage of your 1 Rep Max that weight is.

For example, let’s say you can bench press 150 pounds for at most 10 reps. Using the chart and formula above, you can see that 10 reps on the chart would mean that 150lbs is 75% of your 1-RM. You would then plug those numbers into the formula:

1 RM = Weight / %1RM

1 RM = 150lbs / 75%

1 RM = 150lbs / .75

1 RM = 200lbs

Through these calculations, your estimated 1 rep max would be about 200 pounds. To perform this safely, test the exercise with around 190 pounds first, and move up in safe increments of 2.5 or 5 pounds to 200, or beyond, as needed.

Whether you’re looking to max out your weight on an exercise, or looking to progress and increase your weight safely and break through a plateau, using 1 Rep Max calculations can help you achieve your goals. Knowing more about your strength and power is extremely helpful all throughout your fitness journey.