One Rep Max Calculator

Learn your estimated one rep max so you can target your strength goals more effectively.

Why check your one rep max (1RM)?

Knowing your one rep max isn’t just important for tracking strength increases. It can be used to achieve all training goals more efficiently and affectively. Your one rep max can be used to train for strength, size, and power.

This is why training programs are frequently set up with percentage based lifts. The percentages are based on your one rep max because the program does not know your strength level. They do know what percentage, relative to the 1RM you should be using on that lift though.

Testing for your one rep max shouldn’t be done frequently though, as it is very hard on the body. The good news is that there are great ways to estimate it. For example: the one rep max calculator above.

Calculate your 1RM’s then jump on in to a training program to use them to grow!

How to test one rep max.

When using a one rep max calculator like the one above: the lower the number of reps achieved, the more accurate your estimated max will be. For example, if you enter a weight you got three reps on, it will be more accurate of a calculation than a weight you got 12 reps on.

When testing for an estimated 1RM, stop when form breaks down. Injuring yourself trying to get a higher max will be counterproductive to your long term goals.

Similar lifts will not have the same one rep max. Don’t calculate for bench and then try to use that max for incline bench.

If you want to know your true one rep max use the method below.

Finding your true one rep max.

More experienced lifters will benefit more from a true one rep max test as theirs is less likely to change as quickly. Here is a proven method from Layne Norton for finding your true one rep max. Rest as much as you need to between sets and if you feel stiff while completing the warmup feel free to add a couple sets in. Just don’t go overboard and tire yourself out.


  1. 30% estimated 1RM for 8 reps
  2. 40% for 6 reps
  3. 50% for 4 reps
  4. 60% for 2 reps
  5. 70% for 1 rep
  6. 80% for 1 rep


  1. 90-94% of estimated 1RM for 1
  2. 96-100% of estimated 1RM for 1
  3. 100-104% of estimated 1RM for 1

It is important to use a spotter or another similar safety precaution when testing one rep max. There is no point in injuring yourself!

What Percentage to use for Training

Trying to increase speed and power? You should be using 50-60% of your one rep max and doing 3-5 reps per set for the best results.

If your goal is muscle size use 70-80%. Your rep range should be between 8-12 for maximum results.

Strength oriented goals? Train in the 85-95% range using 3-5 reps per set.

These numbers aren’t the only way to train, they are just some recommendations bases on methods that have been show to give results. There are other ways to get results. Don’t be afraid to try new methods and mix things up.

UXO Creatine has been shown to increase your one rep max.

Creatine has been proven to increase one rep max

If you are trying to increase your one rep max, 5 grams a day of creatine should absolutely be part of your supplement regimen.

Did you find the one rep max calculator useful?

Let us know in the comments!