The purpose of this calculator is to allow a lifter to input the weight, reps, and Rate of Percieved Exertion (RPE) for his or her last set, and then to use either an RPE-based or percentage-based approach to estimate the correct load for the following set.

In the first section, **Your Last Set**, input your weight for your set, and select the number of reps and the RPE of the set.

If your prescription is RPE-based, use the first tab, **RPE**, to select the number of reps and the desired RPE of the following set.

If your prescription is percentage-based, select the second tab, **% backoff**. Select the desired number of reps and the % backoff, as well as the basis set for this backoff. For example, if your program says to do 1@8, and then a set of 5 at -15% from this top single, you'll select "5 @ -15% from 1 rep @ RPE 8". Even if you overshot your last set and did a single at, say, 9.5, this option will first calculate your e1rm based on your 1@9.5, and then calculate your backoff weight from the estimate of what your correct 1@8 weight would have been today.

Hit **Calculate**, and at the bottom, the app will give you the estimated load for your next set and your current estimated one-rep max.