Repetition Maximum Explained: What It Is, How To Calculate It, And How To Apply It To Your Training

What is a repetition maximum

“Repetition maximum”, “rep max”, and “RM”- you’ll often hear these phrases in the world of fitness, weight training, strength training, bodybuilding, and powerlifting. But what exactly does it mean?

A repetition maximum, or “rep-max”, refers to the maximum amount of weight a person can lift for a given number of repetitions in a specified exercise. It’s a measure of the maximum force someone can generate and is used to calculate working loads for reps.

When I first started weight training over 5 years ago, I saw this term banded around all the workout programs I was researching.

It left me stumped and unable to proceed with said workouts.

This article will share my research and experience on exactly what an RM is, how to calculate your RM, and how to apply different RMs to reap different training benefits.

Let’s go!

Choosing the right repetition maximum helped me to build 40 pounds of muscle.

What Is A Repetition Maximum?

Here’s how the National Academy of Sports Medicine (NASM) defines a rep max:

“Your rep max is the maximum weight you can lift for a given repetition for a given exercise.”


It’s important to note that all RMs are measured in the context of reps within a single set (a set refers to a round of consecutive reps performed without resting)

Therefore your 1 repetition maximum (1RM) is the heaviest you can lift for 1 rep in a set, a 2 repetition maximum (2RM) is the heaviest you can lift for 2 consecutive reps in a set, and so on.

Generally speaking, 3-5 sets are recommended per exercise per workout.

Note: it’s still possible to build muscle and strength using less sets, but you need to properly structure your program. Check out my other article to learn how 2 sets can be enough to build muscle.

Why Is Repetition Maximum Important?

There are two important reasons to determine a repetition maximum. Firstly, it allows a person to gauge their relative strength. Secondly, it standardizes the weight used in a given exercise. Therefore a repetition maximum is important for following and structuring a training program.

1. Gauging a person’s relative strength.

Personal trainers and coaches often test their client’s 1-rep max as standard protocol.

This allows the trainer to objectively determine how strong someone is. And this in turn decides how much weight the client should lift to accomplish a specific training goal most safely.

Whether the goal is to build muscle, increase strength, burn fat, tone, or a combination of goals, the 1-rep max is the first step in deciding the training load to be used for reps.

Calculating the 1RM is also something you can do for yourself (more on this later).

2. Standardising weight training programs.

Different people have different strength levels.

Therefore it makes sense for weight training instructions to be standardized for everyone based on their relative strength (allows the program to be used by people of all abilities).

This is why exercise instructions will often quote “% of 1RM” or “8-RM” as the weight to be lifted.

% of 1RM simply means x-percent of your 1-rep max.

For example: 80% of a 100lb 1RM = 80lbs.

Similarly, 8-RM refers to a weight that you can lift for 8 reps.

For example: if you can just about lift 80lbs for 8 reps, then you’re 8RM is 80lbs.

The Rep Max Calculator And How To Use It

There are different types of rep max- and they’re all based on the number of repetitions you perform.

Additionally, each type of rep max is performed for a specific training goal in mind.

Here’s how an RM is calculated as a percent of your 1RM and the goal it serves in weight training:

Rep Max (RM)Reps Per Set% 1RM For Working RepsHow To CalculateTraining Goal
1RM1100%1RM x 1.00Test maximum power
2RM295%1RM x 0.95Power
3RM390%1RM x 0.90Power
4RM488%1RM x 0.88Power-strength
5RM586%1RM x 0.86Strength
6RM684%1RM x 0.84Strength
7RM782%1RM x 0.82Strength-hypertrophy
8RM880%1RM x 0.80Strength-hypertrophy
9RM978%1RM x 0.78Strength-hypertrophy
10RM1075%1RM x 0.75Strength-hypertrophy
11RM1170%1RM x 0.70Strength-hypertrophy
12RM1265%1RM x 0.65Strength-hypertrophy
13RM1360%1RM x 0.60Hypertrophy
14RM1455%1RM x 0.55Hypertrophy
15RM1550%1RM x 0.50Hypertrophy
16RM+16+45+1RM x0.45+Endurance

For the sake of simplicity, each RM has been designated a specific training purpose (see table above).

But in reality, the effects of each RM lie on a continuum (see next).

In other words, all the RMs lead to muscular power, strength, hypertrophy, and endurance gains. What differs is the extent to which they lead to these effects.

The Repetition Max Continuum

The repetition max continuum is a model to describe how repetition and weight load affects training goal optimization. The model states that different rep numbers and training loads will lead to varying degrees of muscle power, strength, and hypertrophy gains.

Here’s the full repetition max continuum and how it affects training outcome:

Repetition maximum range continuum.

Now you can see- although the 2RM emphasizes power gains, it will also lead to some hypertrophy (muscle growth) as well.

Similarly, a 15RM is great for optimizing hypertrophy, but it will also lead to a degree of strength gains too.

So the question becomes:

“Which training goal do you wish to optimize?”

Once you’ve decided on a specific goal to optimize, you can then choose your desired RM and calculate how much weight you should be lifting for that RM (see table above).

1-Repetition Maximum

A 1-repetition maximum (rep max) is used to measure absolute power generation for a given exercise. It can be determined by lifting 60-80% of the estimated 1RM, resting for 3-5 minutes, and progressively adding weight after each rest until failure. It can also be estimated with a strength database.

How to determine 1-rep max infographic.

Detailed 1RM protocol.

By now, you’ve probably realized that the 1-rep max is fundamental to calculating you’re other RMs.

This makes it important to determine you’re 1RM as accurately as possible.

Here’s the American College of Sports Medicine (ACSM) protocol for calculating 1RM:

  1. Warm-up by doing 5-10 reps at 40-60% of the estimated 1RM.
  2. Rest for 1 minute whilst performing static stretches.
  3. Perform 3-5 reps at 60-80% of the estimated 1RM.
  4. Rest for 3-5 minutes.
  5. Add 5-10lbs and perform a single repetion. If successful, continue to steps 6. and 7.
  6. Rest for 3-5 minutes and perform another single repetiton.
  7. Continue resting and adding weight until failure.
  8. Record weight of the failed attempt (1RM).
IUPUI Lab Instructional:: ACSM 1 Rep Max Bench Press
Here is ACSM’s 1-rep max protocol in action.

Ideally, you should reach you’re 1RM within 5 attempts. This will reduce the likelihood of fatigue affecting your 1RM.

It’s also important to have a spotter on standby to assist with any failed attempts.

How to estimate the 1RM.

If you don’t have a spotter available, the safest alternative is to estimate your 1RM.

This can be done by determining you’re current body weight and training level (novice, beginner, intermediate, advanced, or elite).

How to estimate your 1RM using the a database.

Now you can go on the Strength Level Database, locate the desired exercise, and it will give you the average 1RM based on hundreds of thousands of user-generated lifts.

This method isn’t as accurate as the ACMS 1RM protocol, but it’s much safer for beginners and those training solo.

Typical 1RM for beginners.

Assuming the average male weighs 200lbs and the average female weighs 170lbs, here are the typical beginner 1RMs for the 5 main barbell compound lifts:

Barbell ExerciseAverage Male Beginner 1RMAverage Female Beginner 1RM
Bench press136lb / 62kg51lb / 23kg
Shoulder press85lb / 39kg36lb / 16kg
Bent-over row116lb / 53kg41lb / 19kg
Squat184lb / 83kg84lb / 38kg
Deadlift219lb / 99kg104lb / 47kg

These numbers are based on the Strength Level database. A beginner is someone who has been practicing the exercise for at least 1 month.

2- And 3-Repetition Maximum

A 2- and 3-repetition maximum (RM or rep max) is used to optimize power gains for a given weight training exercise. It’s defined as 95% to 90% of the 1-rep max and can be calculated by multiplying the 1-rep max by 0.95 or 0.90, respectively.

Muscular power is defined as the production of maximal force over the shortest period. Examples of power include powerlifting, explosive jumping, and punching.

Training in the 2RM and 3RM range is optimal for muscular power.

How to calculate 2- and 3-RM.

  1. Determine or estimate the 1-rep max. See previous section for “1-RM protocol”.
  2. Multiply 1-RM by 0.95 for a 2-RM.
  3. Multiply 1-RM by 0.90 for a 3-RM.

4-, 5-, 6-Repetition Maximum

A 4-, 5- and 6-repetition maximum (RM or rep max) is used to optimize strength gains for a given weight training exercise. It’s defined as 88%, 86%, or 84% of the 1-rep max and can be calculated by multiplying the 1-rep max by 0.88, 0.86, or 0.84, respectively.

Muscular strength is defined as the ability to overcome resistance. It’s very similar to power but differs slightly because- unlike power- strength does not take into account how quickly the force is overcome.

Therefore it’s possible to be strong but not powerful.

Strength examples include lifting a heavy weight for multiple reps, uphill cycling, and pushing/pulling against an opposing force.

If you’re unsure whether or not you are getting stronger from your workouts, you might be interested in my other article to find out the 13 signs of strength and muscle gains.

Training in the 4RM, 5RM and 6RM range is optimal for muscular strength.

How to caclulate 2- and 3-RM.

  1. Determine or estimate the 1-rep max. See previous section for “1-RM protocol”.
  2. Multiply 1-RM by 0.88 for a 4-RM.
  3. Multiply 1-RM by 0.86 for a 5-RM.
  4. Multiply 1-RM by 0.84 for a 6-RM.

7-, 8-, 9-, 10-, 11-, 12-Repetition Maximum

A 7-, 8-, 9-, 10-, 11- and 12-repetition maximum (RM or rep max) is used to optimize strength and hypertrophy. It’s defined as 82%, 80%, 78%, 75%, 70% or 65% of the 1RM and can be calculated by multiplying the 1RM by 0.82, 0.80, 0.78, 0.75, 0.70, or 0.65, respectively.

Muscular hypertrophy describes the process of increasing muscle size.

Since this rep range strikes a good balance between strength and hypertrophy, you’ll also find this to be the most popular rep range in the majority of general weight training programs.

Training in the 7RM, 8RM, 9RM, 10RM, 11RM, and 12RM range is optimal for balanced strength and hypertrophy gains.

How to calculate 7-, 8-, 9-, 10-, 11-, and 12-RM.

  1. Determine or estimate the 1-rep max. See previous section for “1-RM protocol”.
  2. Multiply 1-RM by 0.82 for a 7-RM.
  3. Multiply 1-RM by 0.80 for a 8-RM.
  4. Multiply 1-RM by 0.78 for a 9-RM.
  5. Multiply 1-RM by 0.75 for a 10-RM.
  6. Multiply 1-RM by 0.70 for a 11-RM.
  7. Multiply 1-RM by 0.65 for a 12-RM.

13-, 14-, 15-Repetition Maximum

A 13-, 14- and 15-repetition maximum (RM or rep max) is used to optimize hypertrophy gains in isolation-type exercises. It’s defined as 60%, 55%, or 50% of the 1-rep max and can be calculated by multiplying the 1-rep max by 0.60, 0.55, or 0.50, respectively.

Isolation-type exercises work single muscles at a time. They include small lifts like the bicep curl (you can check out my other article to find out why biceps respond best to high reps), lateral raise, tricep extension, dumbbell chest fly, leg extension, etc.

From my research and experience, these exercises respond better to high-volume training by performing more reps, compared to compound lifts like the bench press, shoulder press, squat, etc which respond better with heavier weights and lower reps.

The 13RM, 14RM, and 15RM range is optimal for small isolation exercises like the bicep curl.

How to calculate 13-, 14, and 15-RM.

  1. Determine or estimate the 1-rep max. See previous section for “1-RM protocol”.
  2. Multiply 1-RM by 0.60 for a 13-RM.
  3. Multiply 1-RM by 0.55 for a 14-RM.
  4. Multiply 1-RM by 0.50 for a 15-RM.

5 Ways To Increase Your 1-Rep Max

If you’re RM is plateauing, you’ll need to find creative ways to break that plateau to continue getting stronger.

Here are 5 tips I used to increase my repetition maximum:

1) Progressive overload regularly.

This is the first and most obvious way to increase your 1-rep max.

Progressive overload requires you to add weight to your lifts every 1 or 2 weeks.

Many people follow the 5/10% rule – add 5% weight to your isolation lifts and 10% to your compound lifts.

This worked well for me.

But there might come a point where a 5/10% increase begins to become too much (your form breaks down and you simply can’t lift the extra weight).

At this stage, you can try the 1% rule:

“Increase your 1RM by 1% for each rep you complete over the prescribed rep range for your current lift.”

Giovani Grassi, C.S.C.S Strength Coach

For example: if your bench press 8RM is 100lbs, and you can now do 9 reps, then add 1lb (1% of 100lb is 1lb)

This method allows you to apply progressive overload more frequently, albeit to a lesser degree.

If you’re struggling to build muscle, you may be interested in my complete guide to gaining your first 10 pounds of muscle.

2) Consume a bulking diet every day.

Beginners may find strength gains occurring regardless of any diet optimization. This is due to the honeymoon period known as “Newbie Gainz”.

But this phase will end within a few months.

And at that point, you’ll need to consume a proper protein-rich bulking diet to continue making gains.

“Aim for 0.8-1.0 grams of protein per pound of body weight everyday during your bulk. Any less could result in decreased muscle growth and recovery.”

Mike Dewar, C.S.C.S Strength Coach

If you struggle to eat enough food (common reasons being a low appetite or busy lifestyle), then protein shakes can help a lot.

I use and recommend the MyProtein Impact Whey.

Each scoop contains 21g of protein and 100 calories. It’s delicious, easy to mix, clean, and perfect for making lean strength gains.

The MyVegan Pea protein is a good alternative for plant-eaters.

But if you’re very skinny, then the Optimum Nutrition Serious Mass may be more suitable. Each serving contains 27g of protein and 360 calories.

I also add a scoop of MyProtein Creatine Monohydrate.

Creatine is a natural compound found in low concentrations in all our muscles, where it helps with energy production.

The supplement simply tops up our natural creatine levels and will help generate more power in your lifts.

3) Vary your rep ranges.

Remember how different rep ranges lead to different training results, and how this occurs on a continuum?

Well, a great way to capitalize on all the benefits within the spectrum is to vary your rep ranges.

I do this by alternating between the 3-6RM zone for 1 month and the 8-12RM zone for the next month.

Why does this work?

This 2015 study shows that low and high reps build muscle in different ways – 1) metabolic stress, 2) time under tension, and 3) mechanical tension.

So by switching things up, you’ll reap the benefits of all 3 stimuli.

It’s called periodization- the idea is to keep challenging your muscle with both strength and hypertrophy rep ranges for all-around muscle gains.

The 5x5 program is a great way for beginners and intermediates to build a solid foundation of strength. Go to my other article to learn how to do the 5x5 workout at home.

4) Use bands to increase difficulty.

Resistance bands allow you to vary the strength curve in your lifts.

When used properly, the movement becomes harder as the band stretches, helping you to increase your RM.

I found this method to be great for breaking strength plateaus.

It’s common for powerlifters to loop a band around a barbell. The movement remains the same, but the increased tension from the bands now makes the exercise harder towards the top.

Terry Ramos, Personal Trainer, Barbend
I used resistance bands to increase my deadlift 1 repetition maximum

I use and recommend the Undersun Fitness bands.

Having had 2 sets of budget brands snap on me in the past, I highly recommend spending a bit more for the Undersun bands (they have a lifetime warranty).

They can also be used without free weights- I love doing the banded push-up, band rows, and band squats.

If you’re looking to use bands for these exercises, you’ll also need a pair of gloves to protect your hands from friction burns (cheap ones do the job fine).

I use the Ihuan ventilated neoprene gym gloves.

5) Control you’re breathing.

If you’re breathing is out of sync with your lift, you may find your 1-rep max to be negatively impacted.

“You never want to exhale during the 1RM. Take a deep breath and hold it as you descend and ascend.”


Inhaling on the descent phase of lighter lifts (8-12RM) is fine and recommended.

But during the heavier lifts (1-7RM), it helps to hold your breath during the ascent phase.


I’ve explained what a repetition maximum is, how to calculate it, and how to apply it for the best weight training results.

Determining your 1-RM allows you to gauge your strength levels and serves as the foundation to calculate the training load for your working reps.

More specifically, the 1-RM allows you to calculate your 2RM, 3RM, 4RM, etc (each of which has its training benefits).

And this allows you to follow any weight training program with a weight load that’s suitable for your abilities!

If you’re struggling to build strength, you can also try the tips i shared to increase you’re 1RM.

Has this article helped you to understand the importance of the repetition maximum?

Let me know in the comments below!

You may also be interested in the downloadable Kalibre Blueprint PDF which details exactly how I gained 40lbs of lean muscle (it’s 100% free!). It details the exact exercises and nutrition I used to go from skinny to ripped!

Thanks for reading guys!

Peace Out,


(Biochemistry BSc, Biomedical Sciences MSc, Ex-Skinny Guy)


I'm Kal (B.S, M.S)- a health & fitness writer and owner of Kalibre Fitness. I love to nerd out on weight training and nutrition. My primary interests are in muscle hypertrophy mechanisms and strength development. You can connect with me in the "Contact Us" section below!

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