How to Use 1RM to Maximise Your Workout Potential

How to Use 1RM to Maximise Your Workout Potential

You may have heard the term 1RM.  What does it mean and how does it impact your workout?

A 1 Rep Max represents the maximum weight you can push or pull one time.

So, why should you know this, aside from showing off your skills?

If you’re trying to strengthen and gain muscle or improve in your sport, you can use your 1RM to calculate all sorts of variations to your workout that will help you build muscle faster than any other method.

Why Should You Record Your 1RM?

Fit man performing bicep curl in the gym with heavy weight

Recording your maximum weights is not for the beginner lifter, who is better served starting out with lower weights and perfecting form.

1RM is the for next level up - you’re no longer a beginner, but you want to elevate your workout. Or you’re a seasoned lifter and you want to maximise your efforts

Knowing how much you lift or push before your muscles fail, means you can decide the amount of stress you want to put on your muscles, and that can determine if you grow bigger, stronger, leaner, faster or last longer. You can create a workout specifically designed for your goals.

Reviewing the data can even show strength imbalance between lower and upper body or if you’re overlooking certain muscles.

If you’re involved in sports, your 1RM is instrumental in assessing your capabilities and then tailoring your training program.

In the gym, you’ll know exactly how much you can lift for full muscle gain potential, on each individual exercise.

Not to mention you’ll have numbers to track your progress against.

How to Calculate Your 1RM

There are several ways to calculate your baseline 1RM, but today we're going to focus on the easiest 2 tried and true methods.

1RM Formula Method

The key to calculating your 1RM without trying to work up to it, is to lift a slightly lower weight several times. The formula takes the weight you can lift around 5 times without failing and adds a little bit on top - because you would be able to lift a little more if it was really just once.

Choose your exercise for each muscle you want to record a 1RM for.

  • Lift the heaviest weight you can 5 times.
  • If you can’t do at least 4 reps, take a good rest and then try again with a lower weight
  • If you can do more than 6 reps, take a good rest and then try again with a higher weight
  • Use the formulas below to determine your 1RM for each exercise.
For example:
You can lift 40 kilos, 5 times using your chest:
(40 x 1.11307) + 0.6998 = 1RM of 45.3 kg

Upper Body Formula
Lower Body Formula
(WEIGHT x 1.1307) + 0.6998 = 1RM
(WEIGHT x 1.09703) + 14.2546 = 1RM


% of 1RM Method

Another method requiring a little less math, is to estimate your 1MR by how many reps you are able to complete of any given exercise.

  • Choose a comfortable weight and lift as many reps as you can. The weight should be heavy enough you’re not exceeding 15 reps.
  • Review the chart below to determine your % of 1RM
  • Divide the weight by the % to determine your 1RM

For example:
If you can lift 50 kg, 6 times and no more, you’re lifting at 85% of your 1 Rep Max.
50kg / 0.85 = 1RM of 58.8 kg
# of Reps
% of 1RM


Which Muscles Need a Baseline 1RM?

At minimum, target each large muscle group. Recording 1RM for individual muscles will give you more information still, and this is where you can really get into the data behind your strengths and weaknesses, and overlooked muscles.

Many people forget about working their calves, lats, shoulders, and so on. Testing as many 1RM’s as possible will point out the areas you should be focusing on.

The exercises we’ve listed below are tested as reliable 1RM exercises.  

Seated Row
Back Squat (+ lower body)
Bench Press
Chest Press
Leg Press
Smith Machine Squat
Leg Extension
Shoulder Press
Military Press
Hip Adduction
Hip Flexion
Biceps Curl
Triceps Extension
Triceps Push-Down
Split Squat
Leg Curl
Lat Pull-Down


How to Use 1RM to Your Advantage

Choose your goal from the table below to figure out how many reps and at what percentage of your 1RM baseline you should be using in your workouts.

% OF 1RM
13 - 20
60 - 70%
7 - 12
70 - 85%
1 - 6
85 - 100%


60-70% of 1RM

Goal: Endurance

Best For: Leaner muscles, endurance athletes and boosting metabolism for up to 12 hours after workout

infographic showing percentage of 1rm for endurance

Why It Works: Doing more reps at 70% of you 1RM, with no rest between sets means you’re training your muscles to last longer by transferring the load from muscle of muscle instead of tiring out quickly

70-85% of 1RM

Goal: Strength & Growth

Best For: Anyone who wants to build strength and stimulate muscle growth.

infographic showing percentage of 1rm for strength

Why It Works: There’s a reason this is the standard % of max weight for most gym-goers. A moderate number of reps with a reasonable but hefty weight will “damage” your muscles enough to  repair and rebuild thicker and stronger

85-100% of 1RM

Goal: Strength & Power

Best For: Performance athletes who need speed along with strength

infographic showing percentage of 1rm for power

Why It Works: A low number of reps performed at a fast speed (while maintaining form) trains your muscles to respond quickly and with a lot of power.

  • The closer your weight gets to your 1RM, lower the reps - No more than 1-3 reps for 90% or higher.
  • Don’t train at higher than 90% 1RM for longer than a few weeks. Switch to a lower rep workout and give your muscles a much needed break.

Test Your Muscles with 1 Rep Max

Taking the time to calculate your baseline 1 Rep Maximum weight for each muscle group means you can use that information to max out your potential in your workouts.

  • Calculate Your 1RM for all the main muscle groups in your upper and lower body 
  • Determine the % of your Baseline 1RMs you should workout with to meet your goal
  • Maximize your muscle potential with every workout for faster results than ever