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!

1 rm 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 to use the 1RM estimator

Whether you're a beginner or seasoned athlete, thes 1RM calculator isa 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 one 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. This one rep max strength calculator work for most barbell strength exercises; bench press, back squat, front squat, deadlift, trapbar deadlift, overhead press and more.

1RM estimation with this calculator is less effective on Olympic movements such as the Clean and Snatch.

Most accurate max strength calculator

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 ways to measure your one rep max

The rep-max approach to estimating your 1RM is not the only way to find your strength levels.

On this site, you will find a number of calculators and training tools that allow you to measure your strength in the gym from submaximal training data. Two of my favourites are to perform a submaximal set and then converting load, RPE and rep data into a 1RM or generating a load-velocity profile from the data produced with a barbell velocity tracker app. Both are accurate methods and do not require a maximal effort set, using data from regular training data only.

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 about 1RM:

A lifters guide to 1RM strength testing →

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Maximise your workout effectiveness by monitoring key metrics like velocity, power, range of motion and tempo with just your smartphone.

Metric VBT automatically calculates your 1RM from bar speed data, along with bar path tracking, RPE logging and a full workout builder.

Metric is the perfect lifting app to refine your technique and enhance your strength.

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