One Rep Max Calculator

Learn your estimated one-rep max (1RM) using the one rep max calculator so you can target your strength goals more effectively.

Repetition Percentages of 1RM

RepetitionsPercentage of 1RM

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 that don’t require lifting your actual one rep max. For example: the one rep max calculator above.

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

Learn more about one rep max calculator accuracy here or read our own article about it.

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.

Use the 1RM Warm-up Calculator or keep reading for another method below!

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

When testing one rep max, it is essential to use a spotter or another similar safety precaution. There is no point in injuring yourself! If you don’t have access to a spotter, using the one rep max calculator is recommended.

In fact, it is recommended that you only test for your true 1RM a few times a year. You can find other alternatives in this article.

How to Test One My One-Rep Max

Often, trainers and coaches set up programs using your one-rep max as a reference point as they do not know your actual strength level. This allows the trainer to set an effective program without knowing your current strength.

Here are some things to remember when testing your 1RM:

  • The lower your reps, the more accurate your estimate will be
  • Don’t count reps with bad form for the one rep max calculator
  • Remember that each lift has its own 1RM- Don’t use bench to calculate incline bench

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 you intend to increase your speed, try these workouts!

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. New to strength training? Try this workout!

Make sure you get enough calories to increase your size and/or strength. No matter how good your training is, if you don’t eat for results, you won’t get them.

These numbers aren’t the only way to train; they are just some recommendations based on methods that have been shown to give results.

There are other ways to get results. Don’t be afraid to try new methods and mix things up. The one rep max calculator is meant to be a tool, not the answer to your strength concerns.

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

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! Don’t have a program for increasing your one rep max? Find a training program here.