Estimated 1RM for the Big 3

*Thanks to Casey Butt for allowing me to use his formulas

Casey Butt wrote the book ‘Your Muscular Potential’ and is known for his maximum muscle calculator.

Interestingly enough, he has done some other number crunching in an attempt to predict the maximum strength potential for trainees based on their joints.

They are as follows:

Estimated 1RM of the Big 3

Bench press = wrist^3
Oly Squat = 0.37*ankle^3 + 0.59*wrist^3
Power Squat = 0.40*ankle^3 + 0.65*wrist^3
Deadlift = 0.425*ankle^3 + 0.7*wrist^3

Where wrist circumference is measured on the hand side of the styloid process (the bony lump at the wrist) and ankle circumference at the smallest point.

Wrist and ankle refer to the respective circumference in inches, and the estimated lifts are in pounds.These numbers refer to those who are “gifted” so to speak.

…with the “hardgainer” and “typical” being somewhere in the 83% to 86% range of those. No equipment other than a lifting belt was allowed. These lifts were done by lifters under 15% body fat or so – it’s possible to bump the lifts up a little by getting fatter (ala Hepburn, Anderson, current 242+ lb lifters).

To avoid confusion, there are a few caveats to note:

Bench Presses are done in strict fashion, no lifting the glutes off the bench and a full dead stop at the chest. Olympic Squats are ass-to-the-floor and Power Squats are to at least parallel.

The equations assume some balance between the upper and lower body. Hence if your ankle measurement is proportionately greater than your ankle, the equations are likely to underestimate the squat and deadlift. The converse is true for those whose wrist is proportionately bigger than their ankles. A possible equation to determine “proportionality” is: ankle circumference x .806 = wrist circumference

Small-structured and lighter lifters might exceed the predictions as well; you’re not going to find super-heavyweights deadlifting 3 times their bodyweight as often as a lightweight.

If these equations prove to be inaccurate, Casey has also come up with some equations based on bodyweight, which he elaborates in the article ‘Predicting Maximum Strength in the Bench Press, Squat and Deadlift’.

With the caveats stated, a calculator is available below to predict your performance in the Big 3.

The first half of the calculator determines your lifts based upon joint size. The second half determines your lifts based upon your bodyweight at your natural potential assuming that you are at 10% body fat.

Note that these are simply predictions, and should be treated as any prediction should. Anecdotal evidence tells us that these values give realistic goals for the natural trainee, and should likely be treated as minimums in your lifting career.

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