"Same weight, same reps as last week — so why did that set feel so much harder?" If you're only logging weight and reps, moments like this never make it into your records. RPE (Rate of Perceived Exertion) is a simple way to put a number on that feeling.
What RPE actually is
RPE is a self-reported score for how hard a set felt, based on your own sense of how many more reps you had left — not something measured by a device like a heart rate monitor. It originated in endurance training, but it's now widely used in strength training as well, as a way to track intensity that weight and reps alone can't capture.
The 7–10 scale
Strength training typically uses a 10-point scale, and in practice most lifters only log values from 7 to 10:
- 7 — You could comfortably do about 3 more reps
- 8 — You could do about 2 more reps
- 9 — You could do 1 more rep
- 9.5 — You might be able to do 1 more rep, but you're not sure
- 10 — You couldn't do another rep — full effort
Anything at 6 or below is considered clearly within your comfort zone, so it's usually treated more like a warm-up than a working set for strength or hypertrophy goals.
Why log RPE alongside weight
Weight and reps tell you what you did, but not how much it actually cost you. The same "80kg × 8" might be an RPE 9.5 on a poor night's sleep and an RPE 7 when you're fresh. Over time, this extra layer of data reveals things a raw weight chart can't — how your condition fluctuates day to day, and whether there was room to push harder than you did.
It's also a practical decision-making tool: if you hit your target reps at a low RPE, that's a signal you can probably increase the weight next time. If the RPE was already high, it might be smarter to stick with the current weight a bit longer before pushing further.
How to start using it
You don't need to log RPE on every single set from day one. Start with your main lifts — ideally just the last (hardest) set of each — and build the habit from there. As it becomes second nature, extend it to every working set (skipping warm-ups), and you'll start to notice patterns in how fatigue builds up across a session.
Consistency matters more than precision here. Your internal sense of "RPE 8" will get sharper the more you use it, even if your first few ratings feel like guesswork.
Related articles
- What Is Progressive Overload? The Basic Principle Behind Every Gain
- Training at Multiple Gyms? How to Keep Weight Logs Separate
LiFTY lets you log RPE with a single tap — 7, 8, 9, 9.5, or 10 — right on the set logging screen. Start simple with weight and reps, and add RPE or notes whenever you're ready. No account needed to start right away.
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