One Rep Max
Calculator
Quickly and Easily Get an
Accurate Estimate of Your One Rep Max!
KGS LBS
KG
LB
Your one rep max is:
One Rep Max
KG
LB
(lb)
(kg)
Weight to Lift
Percentage of 1RM
Reps to Perform
100%​
100%​ of one rep max
1
95%​
95% of one rep max​
2
90%​
90% of one rep max​
4
85%​
85%​ of one rep max
6
80%​
7-8
80%​ of one rep max
75%​
75% of one rep max
10
70%​
70% of one rep max
12
60%​
60% of one rep max
15-20
50%​
50% of one rep max
30
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One Rep Max FAQs
In here, we'll share some of the most commonly asked questions surrounding one rep maxes and their uses in terms of workout programs.
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What Is a One Rep Max?
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A one rep max (1RM) is the absolute heaviest amount of weight that a person can lift on a given exercise for a single repetition (and no more).
Why Do I Need to Know My One Rep Max?
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It's useful to know your one rep max for a number of different reasons. We'll briefly list each one and explain why it's important.
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Better Programming
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For starters, it's going to be useful in helping you find the right number of reps to do during each working set and hit the right intensity.
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By knowing your one rep max, you're going to be able to hit the right number of reps without wasting all your energy, and without risking using too much of it and burning out.
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For example, take a look at the table above (after plugging in some values).
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If your workout routine says to do 4 sets of 6 reps on the deadlift for instance, it's going to be useful to know your one rep max so that you know the rough amount of weight you'd be able to use to perform 6 reps with.
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Improved Coaching
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Knowing your one rep max is also going to help you train more efficiently if you're got a personal coach or trainer, or just someone that guides you when you work out.
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It's going to make your coach's job much easier if you know your one rep max, as he or she doesn't have to waste time doing any time trying to find the right weight for you to lift.
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Plus, you knowing your true one rep max is also going to be more helpful in aiding your coach to design your workout programs over having to go onto a calculator like this.
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Although our calculator is very accurate, there's a chance that it's not going to be 100% precise to your actual one rep max.
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After all, the best way to know your one rep max is to test it out.
Better Awareness of Your Own Ability
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Knowing your one rep max is also going to increase your self awareness and confidence in your own capabilities.
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If you're proud of your one rep max, and you're confident in your ability to lift heavy weight, it's going to go a long way in helping you train hard and ultimately see lots of good results with your fitness progress.
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If you know your own abilities and have trust in them, it's never a bad thing.
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Who Needs to Know Their One Rep Max?
Not everybody needs to know their one rep max. However it is almost always going to be beneficial for most serious athletes to know what these numbers are.
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Even if you just have a rough estimate of it by using this calculator and plugging in some recent sets that you took close to failure, it's going to be enough.
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However the more advanced you get in terms of your fitness experience, the more important and useful it's going to be for you to know your one rep max.
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As you start to create proper fitness goals and really start to evaluate your performance, it's going to be useful to know your max numbers.
How Often Should I Test My One Rep Max?
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Contrary to what you might see teenage gymgoers do when they first start out (we know many of us were guilty of this), you don't need to be maxing out on your lifts every single week.
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If you're a non-competitive lifter, meaning you don't train to compete in some sort of lifting competition like a powerlifting meet, then you don't really need to be maxing out more than once or twice a year.
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Many of the top powerlifters in the world (whose jobs are to get better at one rep maxes) don't even do it more than twice a year.
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And if you are a competitive lifter, your coach will be able to tell you how often you should be maxing out.
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