Easy 1-rep max calculation.

Here's a simple way to calculate your progress - convert your lifts into your one-rep max.

Let's say you did 10 x 135 pounds. Ten repetitions with an olympic bar and two 45-pound plates. How much could you do for 1 rep?

You could use a One Rep Max Calculator or carrying a poundage chart around, but sometimes you need to do it in your head.

Wikipedia has this following method as formula one in their article, but I converted it to three easy steps for us mathophobes.

One Rep Max
Step 1: Subtract 1 from the number of reps you did. Divide this number by 30. Don't worry about repeating digits past the first three, they don't matter much. Example, 10 reps would be 9/30=0.333

Step 2: Add one to that number. Example: 0.3+1 = 1.3

Step 3: Multiply the weight you've lifted by this number. Example: 1.3 x 135 = 175.5.


Once you do this a few times, you can get a feel for how to wing it.

11 reps? That's 1 and 1/3 of the weight. So one-third of 135 is 45, so 135+45=180.
10, 7 or 4 reps? 30%, 20%, and 10% more than the weight on the bar. Take 1/10 of the weight and multiply it by 3, 2, or 1. 10x135 is roughly 175, 7x135 is roughly 162.5, 4x135 is roughly 150, rounded off to numbers much easier to add to a bar!
6 reps? Tricky at around 17%, but find 1/3 and half that and add it. 6x135 is just under 160, so if you did 6 reps you might round up to 160 and with 5 round down to 155.

A calculator makes it all easier, and it's a simple method to remember. Like all of these calculators it's really approximate. You might be able to do more or less reps for a given weight than the calculator says. But it will let you compare your progress if you use the same calculator each time.

This will let you compare really disparate reps and weights. Is 9 x 125 pounds better or worse than 6 x 135? What about 12 x 20 pounds versus 15 x 15 pounds? That time you did 10 x 225 versus the time you did 2 x 275, how do they match up? Now you know how to find out easily...