One Rep Max


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One Rep Max (ORM) Calculator

Your ORM is the maximum amount of weight you can lift for a single repetition of a given exercise through a full range of motion with proper technique, assuming you are fully warmed and rested. 

Beyond bravado and bragging rights, knowing your one-rep max helps to maintain optimal workout intensity (and in turn achieve optimal results). It allows you to train hard enough to get the maximum muscle-building stimulus out of every workout, without training so hard that you increase the risk of getting injured or running into symptoms related to overtraining.


The issue with a ‘true’ ORM is that the attempt itself, is:

i.     Risky
ii.    Time-consuming
iii.    Exhausting


To perform a ‘true’ ORM test, the correct approach should be to train with light weights and low volumes for several days prior to the attempt to ensure the athlete is fully rested. The athlete is then required to push very close to muscular failure which heightens the risk of technique break-down and injury. Lastly, the attempt will likely leave the athlete drained in the days following the attempt.
Formulae and equations have been developed to allow the ORM to be derived in a more efficient and far less invasive manner.
The DF PT ORM calculator provides the athlete with the ability to find their 1-rep max and easily program percentages based off of those 1-rep maxes.

ORM Approach

i. Select your chosen compound exercise

ii. Warm up thoroughly

iii. Rest 3/4 minutes

iv. Select a weight you can lift for 7/8 repetitions

v. Prepare to perform with correct form

vi. Perform as many repetitions of the chosen compound exercise as possible before technique/ form deteriorates or muscular failure is reached


vii. Enter the results into the calculator below and note/ date the results

Contact DFPT for more help and information.

The DF PT ORM calculator leverages the 'Epley Formula' where: 

1RM = w ( 1 + (r/30) )

w = weight lifted

r = number of repetitions managed by the athlete 

The formula estimates how much the athlete could have lifted for one repetition based on the maximum number of reps (r) of a lesser weight (w). This method is commonly used in competitions and in many gyms to avoid injuries and to provide a more consistent measure of endurance and strength.

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