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One Rep Max Calculator (1RM)

Estimate your 1RM with easy to use calculator. Utilising seven different and proven methods for measuring your one rep max.

Pro tip: Save this web page to your phone home screen for quick access during your workouts!

1RM calculator

Enter the weight lifted and reps performed to see your predicted 1RM. For a relative score, be sure to also enter your bodyweight

All formula average 1RM:

How measure your 1RM

Whether you're a beginner or seasoned athlete, these 1RM calculators are a great tool to help you accurately predict your strength levels and optimise your training. As a way to measure your 1RM without actually performing a 1 rep max, simply enter the weight and reps performed for any set taken to failure, the online calculator will automatically generate your estimated 1RM for that exercise in absolute terms and relative to bodyweight.

For best results, use data from a set between 2 and 10 reps. These calculators work for most barbell strength exercises; bench press, squat, deadlift, trap bar, overhead press and more. 1RM measurement is less effective on Olympic movements such as the Clean and Snatch.

Most accurate one rep max formula

There are a number of scientifically validated formula for estimating your one rep max. Some are exercise specific, others more general.

Instead of choosing just one, this calculator runs your lifting data through seven of the most popular scientifically validated formulas to provide an averaged 1RM prediction along with the outputs for each of the unique 1RM formulas for comparison.

Always be sure to perform a maximum sets with a spotter present and use proper equipment to ensure safety.

Alternative approaches to calculating 1RM

The rep-max approach to estimating your 1RM is not the only way. Performing a submaximal set and then converting an RPE value to find 1RM or generating a load-velocity profile with a barbell velocity tracker are both accurate methods.

Finally, if you really want to know your 1RM, it might be that you just need to perform a 1RM test, this 1RM warmup calculator provides a detailed guide to how you should perform your 1RM test and the weight selections along the way.

Further reading:

Complete guide to 1RM strength testing →

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