One Rep Max

The One Rep Max Calculator allows you to easily estimate your one repetition maximum when weight training.

Simply enter the amount of weight lifted and the number of repetitions that you lifted it for and click "calculate". More information on calculating one rep max.

One Rep Max Calculator
Please enter the weight used and select the number of repititions and click calculate

One Rep Max Calculation

One rep max calculations (one repetition maximum or 1RM) are useful for estimating the maximum amount of weight you can lift in a single repetition for a given exercise and can be used to help design a strength program.

This calculation is commonly used for the bench press but can be used for any weight training exercise.

Calculating the One Rep Max

When calculating your one rep max, it's preferable to load the weights so that you're able to perform around ten repetitions. You must however take into account the exact number of reps you perform.

One rep calculators may not always produce accurate results as there are many interrelating factors that can affect the calculation but they're very useful as a starting point or a consistent measure.

How to use your One Rep Max

Once you have your one rep max you can use the calculator to find out the appropriate load for any planned number of reps you do (as a percentage of the 1RM). The National Strength and Conditioning Association recommends using 67% or less of your one-rep max for muscular endurance development, whereas 85%+ should be used for strength gains.

You should continually test your 1RM to note performance gains and to evaluate the effectiveness of your training.


The Fitstream One Rep Max Calculator is intended for informational purposes only, and should not be interpreted as specific medical advice. A qualified health care provider should be consulted before making decisions about therapies and / or health and fitness conditions.