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!

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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!

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