The Ultimate RPE & Strength Training Glossary
A complete glossary of RPE terminology, 1RM calculators, and strength training definitions. From bench press max calculators to the RPE scale, find every term explained here.
Walking into a powerlifting gym or opening a modern training program feels like trying to read a foreign language. RPE, RIR, e1RM, RTS—it is an alphabet soup of acronyms that can make a straightforward workout feel like a calculus exam. We have all been there. If you are furiously Googling terms between sets because your coach told you to "hit an e1RM of 405 based on an RPE 8 single," take a breath. The math is actually pretty simple once you define the variables. This glossary is your academic survival guide to strength training terminology.
Core RPE Terminology
RPE (Rate of Perceived Exertion)
The subjective scale used to measure how hard a set felt, typically running from 1 to 10. In lifting, an RPE 10 means maximal effort (no reps left), while an RPE 8 means you had two reps left in the tank. For a deep dive, see our guide on what RPE is in lifting.
RIR (Reps in Reserve)
The exact mirror image of RPE. Instead of rating effort out of 10, it explicitly counts how many reps you could have completed before failing. An RPE 8 is identical to 2 RIR.
RTS (Reactive Training Systems)
The organization founded by Mike Tuchscherer that adapted the RPE scale specifically for powerlifting. When people talk about the "RPE Chart," they are usually referring to the RTS percentage table.
The Language of Effort
RPE rates the feeling (1-10). RIR counts the reps left (3, 2, 1, 0). They are two different languages describing the exact same physical reality.
Calculator and Math Terminology
1RM (One Rep Max)
The absolute maximum amount of weight you can lift for a single repetition with acceptable form. Testing this is highly fatiguing. Whether you call it an onerepmax, a single rep max calculator target, or a max 1 rep calculator goal, the definition is the same.
e1RM (Estimated One Rep Max)
A dynamic, mathematically calculated max based on a sub-maximal set. If you lift 315 lbs for 5 reps at an RPE 8, an e1rm calculator RPE tool uses the RTS chart to estimate what your true 1RM is for that specific day. It acts as a max estimator so you don't have to ruin your nervous system to find your limits.
Quick e1RM Calculator
Autoregulation
The practice of adjusting your training variables (weight, sets, reps) on a daily basis based on your readiness and fatigue levels, rather than sticking blindly to a static spreadsheet or an outdated plansouce.
The "Calculator" Dictionary
We get a lot of searches for specific tools. When your brain is fried from squats, people type in all kinds of things. Here is what they actually mean in the trenches:
| Term | What It Actually Means |
|---|---|
| powerlifting rpe calculator | A robust powerlifting calculator that converts sets, reps, and RPE into an e1RM and generates target weights. Some folks mistakenly search for an rp calculator or an rp cal, but they mean RPE! |
| max lift calculator | A general term for a max pr calculator. Usually, this refers to a tool that estimates your max. Can also be called an orp calculator (one rep max), one-rep max calculator, or even an one tep max calculator when typing with chalky hands. |
| pr calculator | Same as a pr calc or a p r calculator. This helps you know what weight to load for a personal record. |
| reps to max calculator | Also known as a reps calculator. This answers the question: "If I did 315 for 5, what is my max?" You might use a 10 rep max calculator or a 3 rep max calculator depending on the set. |
| max rep calculator bench | A specific tool for the bench press, though the math is identical for the squat and deadlift. |
If you are ready to stop defining terms and start applying them to your workouts, head over to our how to calculate RPE tutorial to put the math into action.
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