How to Find Your 1 Rep Max

Finding your one rep max (1RM) sounds easy – just pick up a weight and try to do the exercise for one rep, right?

If you’re going through a lot of weights to get to that point, it might not be your true 1RM; this method also poses a high potential of causing injury to yourself. Try finding a weight that you can use for 5-6 reps, and have a spotter with you to help you out and assist when your technique begins to waver.

When ¬†you’ve found your 5-6 rep max, you can calculate your 1RM. Using the chart below, multiply your weight by the percent difference of your 1RM, and add that number to your weight. Example: You bench 100lbs, 4 times. The chart states that this is 90% of your 1RM. Multiple 100 by 10%, you get 10. Add 10 to your original 100lbs, and you get 110lbs – your 1RM.

Reps %1RM
1 100
2 95
3 93
4 90
5 87
6 85
7 83
8 80
9 77
10 75

You can also calculate your 1RM with a scientific equation. 1RM=w/[1.0278-(r x 0.0278)] – w is the weight used, r is the number of reps completed. As an example, we’ll use 100lbs for 4 reps.
1RM=(100)/[1.0278-((4) x 0.0278)=109lbs.

Whichever method you use, your results will be about the same. If your looking for something precise, use the equation to find your 1RM; the chart works well for a quick reference.
In the near future, I’ll be blogging about the various forms of resistance training (strength, endurance, hypertrophy, power). The weight used during these different training types, would be a calculated 1RM. So calculate yours, and stay tuned on how you can put it to use!

Steven Moore About Steven Moore

Passionate Personal Fitness Trainer, and NASM Corrective Exercise Specialist at Blitz Conditioning. Prone to spurts of random nonsense. [Read my full bio]


  1. Thank you so much…I wish I would have seen your post before I tried to play HE–MAN at the gym and had to seek medical help because of it thanks again!

Share your thoughts