When to use RPE, when to ignore it

RPE (rate of perceived exertion) rates how hard a set felt. 10 means nothing left, 9 means one rep in reserve, 8 means two. Grain Gym's scale runs from 6 to 10 in half-point steps.

Logging it

RPE is optional and off by default. Turn on the RPE switch under Settings, then Workout display, or in the workout's ⋯ menu, and each set row gets an RPE field. Tap it and the Advanced logger opens for that set, where you pick a value from 6 to 10, or None. The value is saved with the set and shows in your history.

What it changes

Today, a logged RPE doesn't change your next target. Grain Gym's progression rules read the weight and reps you logged, not the RPE, so you can leave it blank without losing anything.

Programs that give you an RPE target

Programs with an RPE-based rule stamp a target RPE and a rep range on the sets, and you choose the weight that fits. Beginner Body Builder, Upper/Lower Split (PHUL), HIT-Inspired Low-Volume Strength, Glute & Curves (Gym Edition) and 5/3/1 Strength all use it somewhere, mostly on accessory work.

For those sets, RPE is the thing to watch. Pick a weight that lands at the target RPE for the reps, log what happened, and use your own history to adjust.

A useful habit

Logging RPE on the heavy lift of the day gives you a record. Two months of 8s on a top set means the work is getting done. A run of 9s and 10s at the same weight means a lighter week is closer than it looks.