This one rep max calculator will allow you to estimate your one rep max with any lift in the gym and percentages of your one rep max to help you design your workouts more accurately.

If you are training and don’t know your one rep max, it is almost like doing cardio and not knowing your heart rate.

You don’t need to be someone in bodybuilding or powerlifting to use this information; all gym-goers can maximize their weight training with this calculator.

What Is One Rep Max?

This one repetition maximum is a vital part of training as it shows how much weight lifters can handle, essentially how strong someone is.

But you don’t always have to test your single repetition max with a given exercise; instead, you can use the 1RM calculator provided here.

This is ideal, as it takes a lot of time and effort to truly test your maximum strength with a one rep maximum test. This means you will have less time in your training program to focus on building muscle.

There are a variety of formulas to use for finding someone’s one rep max.

The most popular formula is the formula from Matt Brzycki, which is weight divided by ( 1.0278 – 0.0278 × reps ).

Epley’s formula is the weight multiplied by (1 + 0.0333 × reps).

Lander’s formula is (100 × weight ) / (101.3 – 2.67123 × reps).

Lombardi’s formula is weight × reps ^ 0.1.

How Can I Test My One Rep Max?

One rep max testing is useful for anyone in weightlifting to understand.

This form of testing is great to know when you plan your compound lifts like the deadlift, barbell bench press, and overhead press, and not movements with body weight.

When it comes to testing your one rep max, the easiest way is to find the max weight you can do for a specific number of repetitions and then plug that into the one rep max calculator we have here.

The lower the number of reps, the more accurate it will be. This is the preferred method, as it will not stress the body as much as a true 1RM test.

So, if you were to find your 5 rep max, this would be the max weight you can do without failing your form for five total reps, and then use the calculator; it would give you your estimated one rep max.

You should try to have a spotter when you are doing any reps to your max weight, and be smart with each rep so you do not injure yourself.

And, as we hinted at, form is everything, and if your form starts to break down, it is a good idea to stop the set you are in and either lower the weight or regroup and try again.

It is important not to count any of the reps that happen once the form is lost, as it would not be a true repetition max test if you continued.

You should remember that you should not interchange these numbers for somewhat similar movements and instead rely on knowing the one rep max for each move, as strength standards are specific. Your front squat weight is not usually equivalent to your back squat, no matter how similar the movement is.

What One Rep Max Percentage Should I Use?

Regarding strength training, the percent of your one rep max will matter depending on the goal you want to achieve.

We generally look at the three goals: speed and Power, Muscle Size, and Strength.

While these can be gained in some way within all three percent and rep ranges, the rep and percent ranges give us an idea of what our focus goal should be with training.

When it comes to Speed and Power goals, we suggest that people lift 50 – 60% of their one rep max, and this would be for 3 – 5 reps per set.

When it comes to hypertrophy and working on the size of muscles, this should be done at 70 – 80 percent of your one rep max and for a total of 8 – 12 reps per set.

The last category is for working on the strength of muscle group, and this would have you working at 85 – 95% of your one rep max and for around 3 – 5 reps per set.

How Can I Use My One Rep Max?

One rep max is not something that you will be trying to reach and achieve very often, but instead, a marker that we use to set our reps and percentages for actual workouts.

No doubt, it is important to test and retest your one rep max occasionally, but if you are trying for it too often, it will tax your body and take away from training.

Even a bodybuilder or powerlifter will not test their one rep max as often as one might think. Powerlifters do work mainly in the lower rep ranges, though.

If you desire to build muscle and grow optimally in your training, you will need to base the percentages and reps we discussed in the last section on your training goal.

How Can I Increase My One Rep Max?

Your one rep max is important to know and test, but it is also important to know that you do not have to work only on one rep max to increase it.

You will naturally increase your one rep max by increasing your strength in all rep ranges, but the lower rep ranges work even better at increasing the type of strength needed for all out strength testing.

So, in a way, all forms of exercise will work to increase your one rep max and don’t forget to reassess it every now and then to check.

We hope you enjoyed our one rep max calculator and find it useful in your personal training or personal workout routines in the gym!

Make sure to check out our other calculators here at PTPioneer.

FAQs About One Rep Max

What is 80% of 1 rep max?

To calculate 80% of your 1 rep max (1RM), multiply your 1RM by 0.80. For example, if your 1RM is 100 pounds, then 80% of your 1RM would be 80 pounds (100 * 0.80 = 80).

What is 50% of 1 rep max?

To find 50% of your 1 rep max (1RM), simply multiply your 1RM by 0.50. For example, if your 1RM is 100 pounds, then 50% of that would be 50 pounds (100 * 0.50 = 50).

How do I calculate my 1 rep max?

Here’s a step-by-step breakdown of the formula:

  • Multiply the number of repetitions you can perform to failure by 2.5.
  • Subtract that result from 100 to determine the percentage of your 1RM.
  • Convert this percentage to a decimal by dividing it by 100.
  • Divide the weight you lifted by this decimal value to get your estimated 1RM.
    For example, if you can lift 100 pounds for 10 reps:

10 x 2.5 = 25
100 – 25 = 75 (This is 75% of your 1RM)
75 / 100 = 0.75
100 / 0.75 = 133.33 pounds (estimated 1RM)

What is the percentage of 1 rep max?

A one rep max (1RM) represents 100%, and each additional rep reduces the percentage by 5% for every two reps. For instance, a two rep max is approximately 95%, a three rep max is around 93%, and so forth. Keep in mind that these values are estimates and can differ depending on the exercise and the individual.

Tyler Read - Certified Personal Trainer with PTPioneer

Tyler Read

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6 thoughts on “1RM Calculator – Estimate Your One Rep Max”

    • When you are trying to find your estimated one rep max for an exercise, the weight refers to the weight lifted, so your own weight would not be relevant to the calculation. The calculator also only goes up to 12 reps, as the further away from 1 rep you are, the less accurate the answer will be, since all of these would be an “estimated” one rep max. The best possible way to test one rep max is by doing the max amount of weight in one rep. Everything else from 2 to 12 reps will only be an estimate. I hope this information helps.

    • Hey Bruce, if you are doing a real one-rep max test, you aren’t going to be doing multiple sets. In theory, you will be warming up to get to near max values, regardless of if it is a pure one-rep max test or a multiple-rep estimation. The most important part is warming up with something in the range of 3 – 5 sets building up to closer to max values. Have you given it a shot and used the calculator yet?

      • So what I think they, and myself are actually wondering is; If my workout looks like X Lbs for 4×4 with progressive overload how would I calculate my 1RM? In my particular situation running Ivysaur 4x4x8 my deadlift currently looks like 320 Lbs for 3×4+1AMRAP with my last set being for 6. Obviously I can lift 320 for more than 6 if I only did 1 set because fatigue has already set in by that last set. So using 320 for 4 isn’t accurate because I can do more reps at that weight but using 320 for 6 is also inaccurate because I’m already fatigued.

        • When you are testing for a one-rep max, you do not want to fatigue yourself too much, and this is just as true when it comes to an estimated one-rep max. If you are able to do 320 pounds for 3 sets of 4 reps and you are also able to do 320 pounds once for 1 set of 6 reps, then your 1 set of 6 reps is the more accurate estimate. When testing for one-rep max, you will ideally dedicate a gym day to that test. This means if you are warming up for your one-rep max or one-rep max estimate, you will want to slowly warm up with one set of each weight progressing to what you think will be your true max. You are essentially going to failure whether it is a true one-rep max or a multi-rep one-rep max estimation.

          The whole idea of a one-rep max is that is is the most you can lift and it is right on the edge of failure. It is not indicative of your level with which you will be training. But, typically you can use percentages of your one-rep max to find ideal training intensities, too.

          I hope this answer helped. Let me know your thoughts and if you already tested your one-rep max or estimated it with the calculator.


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