1RM vs PR: What’s the Difference?

Key Points:

  • PR stands for Personal Record and it is the heaviest weight you have ever lifted.
  • 1RM stands for one-rep max and is the heaviest weight you can currently lift for one rep.

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As strength training enthusiasts, we are naturally inclined to measure how much weight we can lift in a given exercise. This is sometimes referred to as a PR (personal record), PB (personal best), or 1RM (one-rep max).

But what is the difference between these terms, and when is it important to keep them apart?

Since plenty of our strength training programs are based on your 1RM, I thought I’d take this post to clarify the terms.

1RM vs PR definition

Definitions: 1RM vs PR (or PB)

Let’s define the terms:

  • PR stands for Personal Record and it is the heaviest weight you have ever lifted. A common synonym is PB, or personal best, which carries the same meaning.
  • 1RM stands for one-rep max and is the heaviest weight you can currently lift for one rep. Note the word currently.

Your 1RM can both be higher or lower than your PR. And in contrast to your PR, your 1RM has nothing to do with whether or not you have actually ever lifted it.

Allow me to explain by using examples: one where your 1RM is lower than your PR, and one where your 1RM is higher than your PR.

Example 1: 1RM Lower Than Your PR

Let’s say that you have never lifted more than 90 kg in the deadlift. That is until you have an awesome workout in which you lift 100 kg for one rep, for a PR. It was terribly heavy, and you are absolutely certain that you couldn’t have lifted another kilo. In this scenario and on this day, 100 kg is both your PR and your 1RM.

But then, let’s say that you take a break from training for a few months and your strength deteriorates. On your first day back in the gym, you decide (against better judgment) to max out in deadlifts again. You pull gradually heavier weights, and finally manage to lift 80 kg for a single rep, but you fail at 82.5 kg. On this day your 1RM is 80 kg, even though your PR is still 100 kg.

If you’re planning your training based on your 1RM moving forward, you should plan based on 80 kg.

1RM vs PR in strength training
If you follow 1RM-based programs from our workout app, it’s important that you use correct 1RMs. Otherwise, you won’t be as happy as this young man.

Example 2: 1RM Higher Than Your PR

Let’s stick with the same example.

You get back into the habit of deadlifting regularly again, and you stick to this routine for several months. In all of your training, however, you never use a weight heavier than 100 kg.

You keep working out until the point where you can do ten repetitions on 100 kg in one set. Now: what is your PR and what is your 1RM?

  • Your PR (in a single rep) hasn’t changed. It is still 100 kg. You have never lifted anything heavier in your life, and that is still your record.
  • Your 1RM on the other hand has most definitely changed, as is likely far more than 100 kg. Just because you haven’t measured it, doesn’t mean it doesn’t exist. Just in the same way that you have a body weight and a body temperature even if you would never measure them.

If you were to test your 1RM on this day, you could maybe lift around 130 kg for a single repetition. If you did so (and you couldn’t lift any heavier), then 130 kg would become your new PR and you would also know that your 1RM that day was 130 kg.

However, if you don’t test your 1RM that day, your PR would still be 100 kg, and you wouldn’t know what your 1RM is on that day. Your 1RM would still be 130 kg – you just wouldn’t know.

Your PR is your historically best performance, but your 1RM is a measure of strength that constantly varies up and down, just like your body weight or temperature does. And, just like your body weight and temperature, you don’t have to measure your 1RM in order to have one. It is perfectly possible to have a 1RM of 130 kg even if you have never lifted heavier than 100 kg in your life.

A stranger on the town that has never deadlifted therefore has a 1RM in the deadlift (but no one knows what it is) but he or she does not have a PR.

1RM is a constantly varied, fleeting measurement of your current strength in a single rep. Your personal record is the heaviest weight you have ever lifted. These are not necessarily the same thing.

My personal record in the deadlift is 260 kg, but if I were to go out in my garage gym right now and max out, I don’t think I would have been able to lift more than 240 kg. My PR is 260 kg, but my 1RM is 240 kg.

Another example comes from a study where three participants (two powerlifters and one weightlifter) maxed out in squats every day for 36 days. Meaning, they tested their 1RM every day and got different measurements that varied from day to day.

Daily 1RM Max Squats
Different 1RMs on different days. Their daily 1RM fluctuated between almost -5% to +10% of their starting 1RM.

Practical Application

So what do you do with this information?

The most important thing is probably to use the right weight (1RM vs. PR) when you follow a 1RM-based training program or workout. Let’s say you’re going to follow our popular deadlift specialization program Deadlift Disco, which is based on different percentages of your 1RM. If your two-year-old PR is 200 kg but your current 1RM is closer to 180 kg, then entering the latter when you start the program will likely give you a far more productive training cycle.

1RM deadlift training program
Make sure to enter a 1RM that gives you the most appropriate training weights.

So, when you are about to start a new training program and it calls for your 1RM, think about what you could lift now or perhaps within a week of preparation. If you are experienced, you might even be comfortable adjusting this number up or down depending on what you think will give you the most productive training cycle.

StrengthLog tracks your PR personal records
Our workout app StrengthLog keeps track of all your PR’s in all your rep ranges and exercises – 100% free.

Summary

1RM and PR are two separate things. Sometimes they will be the same number, but this is often only the case during very short periods of time.

Your PR is your historically best performance, but your 1RM is a measurement that varies up and down in the same way as your body weight or temperature.

If you plan your training based on your strength, then it is mainly your 1RM you should base it on. That is your current strength. Don’t base your training weights off of a one year old PR.

One way to estimate your 1RM without maxing out is to use our 1RM calculator, available for free both in our workout app and on the link below. Based on how many reps you can do on a given weight, it will calculate an estimate of your 1RM, as well as your 2–10RM.

Link: 1RM Calculator: Calculate Your One Rep Max