How To Calculate and Use Your 1 Rep Max

The 1-rep max (1RM) is a great tool for anyone looking to increase their strength in the weight room.

It’s both an expression of strength in an exercise movement and an integral way to track progress over time.

This article will explain what a 1RM is, why it’s important, and how to use it in your exercise program for maximum results.

A 1-rep max refers to the maximum amount of weight you can lift for one repetition of a given exercise.

It’s used as a marker of overall strength and power in the exercise. It can also help you estimate how much weight to lift in the future based on the desired number of repetitions.

For example, if you want to challenge yourself with 5 reps of back squats and you know your 1-rep max number for this exercise, you can simply calculate the weight to put on the barbell as 85–90% of your 1-rep max.

According to a review from 2020, finding your 1-rep max is a reliable test of overall muscular strength. This applies to different age groups, males and females, and single-joint or multi-joint exercises (1).

An older 2003 study determined that conducting a 1-rep max test is safe for healthy children and adults as long as they follow appropriate procedures — a finding that’s still cited by research today (2).


A 1-rep max is the most amount of weight you can lift for one rep of a given exercise. It’s been proven as a reliable way to test muscular strength.

Before you make the decision to test your 1-rep max in an exercise, here are a couple of parameters to consider:

  • Safety. If testing your 1RM for a free-weight movement, it’s imperative that you use a good spotter — or at the very least a safety rack for barbell movements. When you fail, there needs to be something or someone to catch the weight to keep you safe from injury.
  • Technique. Pick an exercise you can do with good technique. As the weight gets heavier, it’s easy for your form to get sloppier. If the technique is not dialed in from the start, the tension can target your muscles and joints improperly, which can be dangerous and work against your goals.
  • Experience. A 2022 study found that 1RM testing was not ideal for beginners. Beginners don’t need to max out because their technique isn’t solid yet, which can be dangerous at high loads (3).

To test your 1RM, use the following procedure:

1: Warm up

Warm up with a weight you can comfortably do 6–10 repetitions with, which will be around 50% of your 1RM.

Rest for 1–5 min. How long exactly depends on when you feel 100% recovered and ready to complete the next step.

2: Increase the weight

Increase the weight to a load you can do 3 reps with, which will be around 80% of your 1RM.

Rest 1–5 min until you feel fully recovered.

3: Do your heaviest lift

Increase the load and drop the repetitions to one. Go for the heaviest weight you can lift with good technique. Keep increasing weight until you reach your limit, resting in between tries.

Once you’ve reached the highest weight you can lift for one rep, that is your new 1RM.

Alternative: use a different rep-max and estimate with a calculator

Instead of doing a test, you can estimate your 1-rep max if you know your max amount of strength at a different rep range.

Here’s a calculator to help you estimate your 1RM based on your current personal records (PRs):

For instance, this calculator allows you to use a 10-rep max to estimate your 1-rep max. A 10 rep-max is far less strenuous on the body and joints than doing a true 1-rep max. It’s also safer if you’re new to working out or don’t have a spotter.

That said, the calculated 1-rep max will be less accurate than a true 1-rep max test. With that in mind, your 1-rep max may be higher or lower than what the calculator estimates.


To find your 1RM, you need to gradually increase the weight you use in an exercise and keep moving with good form until you reach your limit. Alternatively, you can estimate your 1-rep max using a higher rep-max and a calculator.

Knowing your 1RM is particularly useful for athletes who compete in a strength sport or competition.

In both powerlifting and Olympic weightlifting, the goal is to lift the most weight for just one rep. In other words, it’s fundamental to know your 1RM so you can decide which weights to lift in competitions and during practice.

Plus, you can use your 1RM to estimate which loads to lift in the gym by referencing the below list. However, note that these numbers are only estimates and that your personal percentages may vary between exercises.

Repetition percentages of the 1RM (4):

  • 1-rep max – 100%
  • 2-rep max – 97%
  • 3-rep max – 94%
  • 4-rep max – 92%
  • 5-rep max – 89%
  • 6-rep max – 86%
  • 7-rep max – 83%
  • 8-rep max – 81%
  • 9-rep max – 78%
  • 10-rep max – 75%
  • 11-rep max – 73%
  • 12-rep max – 71%
  • 13-rep max – 70%
  • 14-rep max – 68%
  • 15-rep max – 67%
  • 16-rep max – 65%
  • 17-rep max – 64%
  • 18-rep max – 63%
  • 19-rep max – 61%
  • 20-rep max – 60%
  • 21-rep max – 59%
  • 22-rep max – 58%
  • 23-rep max – 57%
  • 24-rep max – 56%
  • 25-rep max – 55%
  • 26-rep max – 54%
  • 27-rep max – 53%
  • 28-rep max – 52%
  • 29-rep max – 51%
  • 30-rep max – 50%

A benefit of using percentages of your 1RM for training is that you can standardize the loading. This enables you to accurately track improvements and manage your volume and intensity.


Knowing your current 1RM is essential in many strength sports. It can also be useful for anyone in the gym looking to gauge their strength progress in a standardized format.

As discussed, studies have shown that regardless of your exercise selection, your 1RM can help assess your muscular strength.

A good way to capitalize on this is to pick a few major exercises to test your 1RM and to stick with those across your programming (1).

Strength is exercise-specific. This means that even if your bench press 1RM is 225 pounds (102 kg), your incline press or your overhead press will be different. Try to pick one movement to track per major movement or muscle group, for instance:

  • Bench press: chest/shoulders/triceps
  • Back squat: legs
  • Barbell row: upper/lower back

Then, use progressive overload over weeks to months. To ensure progress, use the percentages of your 1RM to figure out which weights to use based on the rep scheme you’re following.

As you increase the weight, you can simply estimate how much higher your new 1RM is based on the increased load. You can also re-test it and find out.

Here’s an example of a simple strength program using percentages of your 1RM:

  • Week 1: Test your 1RM in the bench press, squat, and barbell row.
  • Week 2: Bench press, squat, and barbell row for 3 sets of 5 reps using 85% of your 1RM from week 1.
  • Week 3–5: Increase the weights in each exercise by 5–10 pounds (2.3–4.5 kg) each week.
  • Week 6: Either re-test your 1RM to gauge improvement or estimate it using your new five-rep max (5RM).


You can use your 1RM in your training programming to ensure progressive overload. After 6–8 weeks, you can re-test your 1RM or calculate it from your 5RM to gauge your progress.

It’s best to wait to re-test your 1RM until the end of at least one training block, if not longer.

Olympic weightlifting athletes often max out every four years, at the Olympics. You likely don’t need that long, though you should wait at least several weeks to months before re-testing to see if your training program is making you stronger. Adaptations take time.

As you get stronger and more advanced, the weights you use get heavier. Maxing out can get increasingly demanding for your joints and connective tissue. The risk of injury also increases.

Conveniently, you can estimate your 1RM using the repetition chart above and gauge your progress that way, without having to perform 1RM tests again.

A 2020 study found that training with loads of 70–85% of people’s 1RM produced significant increases in 1RM. This means you can train at sub-maximal weights and still see strength gains (5).


Wait until the end of the training cycle, at least several weeks to months, to re-test your 1RM. You can use your higher rep PRs to estimate progress instead of re-testing your 1RM.

If you’re interested in strength training, it can be useful to know your 1RM across different exercises.

It can help you assess your current strength, progress, and which weights to add according to how many reps you perform in a training program.

Once you find your 1RM, it’s generally best to wait for at least one training cycle before re-attempting. Until then, try to progressively overload your workouts to get stronger.