One Rep Max Calculator

powerlifter about to attempt 1RM

One Rep Max Calculator

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

Finding 1 rep max can be helpful for understanding your current strength level, building programs, and even more! Find yours below!

Repetition Percentages of 1RM

RepetitionsPercentage of 1RM

Why Check Your One Rep Max (1RM)?

The primary reason to measure and calculate your one rep max is to find your strength level. It tells you how much weight you can lift for a single repetition.

Curious where you stack up against other lifters? Trying to increase your strength? Or do you want to know how much you can bench for a single repetition? Answer these questions by testing your strength level! You can find it with a one rep max attempt or use a calculator like this to calculate your one repetition max.

Knowing Your Strength Level Using One Rep Max Isn’t the Only Reason

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

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 calculator above.

Learn more about one rep max calculator accuracy here.

How to Test One Rep Max.

When using a 1RM calculator: the fewer reps achieved, the more accurate the one rm calculator will be. A 1RM calc like this only estimates based on the information it is given.

Stop when form breaks down. Full range of motion and proper technique are essential to prevent muscle injuries and for accurate fitness calculators results. Besides, injuring yourself to get a higher max is counterproductive to your long term goals.

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

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

NASM 1RM Conversion Chart PDF

Table from the NASM website.

Or you can check out our bench press max chart here for more specific numbers.

How to Calculate Your One Rep Max Using Our Calculator

Learn how to quickly and accurately gauge your one rep max! Save time and begin maximizing your workouts today.

Looking to boost your strength and performance? Use our one rep max calc to accurately determine the maximum amount of weight you can lift for one complete repetition.

This tool takes into account your current strength level. It can also help you build an effective training program to reach your fitness goals.

What is a One Rep Max?

One rep max (1RM) is the maximum amount of weight that you can lift for one complete repetition. Knowing your 1RM can help you build an effective weightlifting program to maximize it.

How Does Our Calculator Work?

It uses a customized equation to accurately determine your 1RM range. It predicts your max based on the amount of weight you can lift for multiple reps.

Provide the weight and number of repetitions. Then it will instantly generate your 1RM. It’s as simple as that!

Which Factors Can Affect Your Estimate?

Factors such as body weight, neuromuscular exhaustion of the muscle from fatigue, and technique variations can affect the calculation. These all have a significant impact on the value estimated.

high angle shot of a woman doing a bench press

Finding Your True One Rep Max

Are you about to attempt a new 1RM? Use the 1RM Warm-up Calculator below! You can also keep reading to determine how much weight you should use to warm up for the best results!

Enter the weight you plan to attempt below. Then the 1RM warm-up calculator will show you exactly what weight you should lift for your warmup.

More experienced lifters will benefit more from a true one rep max test as theirs takes longer to increase. Just make sure to lift safely and intelligently.

Here is another proven method from Layne Norton for finding your true one rep max.

Warming up to a 1 Rep Max

warming up to a squat max

Warming up can make all the difference in your training. It is especially important when you plan on attempting a 1RM. A good warm-up may lower your chances of injury. It also increases the likelihood of a successful PR attempt.

How to Calculate Warmup Sets

Here is a simple and effective way to calculate warm up sets and reps:

  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

Testing for Your 1 Rep Max

  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 it’s of course essential to use a spotter or another similar safety precaution, especially for bench press. There is no point in injuring yourself!

How Often Should You Test 1RM

You should only check your maximum strength once every 3-4 months at most. Lifting loads over 90% of your max can lead to damaged muscles and tendons. It also increases your chances of serious injury and even decreases gym performance.

Testing your 1RM too often can lead to:

Alternatives to Testing Your True Max

Performing a one rep max set isn’t the only reliable way to find your max. Although it is the most accurate, it is also the hardest on your body and will not increase your strength. Here are some safer alternatives.

Multiple Rep Max

One common way to gauge strength on a specific lift is to perform a 2-5 rep max set. This is less dangerous and can be performed about once a month.

This is precisely what 1RM calculators come in handy for!


An RPE-based rep max is similar to a rep test; but, you aren’t taking yourself to true failure with it. 

Say you lift a specified weight for three reps at an 8 RPE (8 out of 10 rate of perceived exertion). If you lift a heavier weight for the same reps at the same RPE, you know you are making progress.

This style of repetition maximum test is significantly easier on the body. It also helps increase strength (unlike a true 1RM test) and can be done about once a week.

How to Find My One-Rep Max with the One Rep Max Calculator

Often, trainers and coaches set up programs using your one-rep max as a reference point. Especially if they don’t 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
  • Remember that each lift has its own 1RM- Don’t use bench press to calculate incline bench press

What Percentage to Use For Training

Speed and Power: 50-60%

Muscle Size: 70-80%

Strength: 85-95%

These numbers aren’t the only way to train, mix up the percentage of 1RM and rep range. They are just some recommendations based on methods that are proven 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.

Not Happy With Your Current One Rep Max?

Here are some tips to help you get those numbers up!

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.

Train Close to Your One Rep Max

Try training at 80% of your maximum for four sets of five on week one. Then week two gradually increase the percentage of your max and so on.

Once you can perform this set and rep scheme for 87% of your max, try testing again.

Perform Walkouts or Holds

Man standing with barbell in back squat position. Walkouts are a great way to increase your squat 1RM

Sometimes you fail to pull off a new max attempt simply because you haven’t ever held that weight before. Simply load up the bar with the weight you want to lift (your 1RM or more). Then unrack it (walk out with it in the case of squats), hold it for a few seconds, and put it back on the rack.

Train Specific Ranges of Motion

If you are getting hung up on a specific portion of a given exercise, try these:

  • Bench Lockout– Use boards or pins to shorten the range of your bench motion to just the top half.
  • Deadlift Lockout– Perform rack pulls, lifting the weight from the mid-thigh position.
  • Coming out of the Hole: Squats- Perform low box squats from below your typical squat depth.

Make sure to work with a spotter any time you training near your maximum.

Follow a Program

If your main exercise goal is to increase your 1RM for a given exercise, follow a strength training program built to do just that.

For beginner lifters or those who have never followed a strength training program, use Stronglifts or a similar program.

Just need to push yourself to the next level? Try other powerlifting programs like Smolov Jr. or browse all of our programs here.

What is the Most Common One Rep Max Calculator Formula?

There are several different formulas. The most common is the weight lifted divided by the total of 1.0278 minus the reps performed times 0.0278. This number is then rounded down to the nearest five.

one rep max calculator formula
one rep max calculator formula

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More 1RM info

Is it bad to test your one rep max?

There are pros and cons to testing your one rep max. You do need to be careful when testing your one rep max.

Doing so overstresses your nervous system and joints, can slow down progress, and carries a high potential for injury. Only test when you absolutely need to.