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RPE Calculator
RTS percentage chart
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What is RPE in lifting?
RPE (Rate of Perceived Exertion) is a 1-10 scale for describing how hard a set felt. It started in endurance training and became popular in strength sports through Mike Tuchscherer’s Reactive Training Systems (RTS).
In powerlifting it’s usually framed around “reps in reserve” (RIR). RPE 10 means you had nothing left, RPE 9 means 1 rep in the tank, RPE 8 means 2, and so on down to around RPE 6, which is about as low as most programs ever bother going.
How the RPE chart works
This calculator uses the RTS chart, which maps an RPE and rep count to a percentage of your true 1RM. A few examples at RPE 8:
| Reps @ RPE 8 | % of 1RM |
|---|---|
| 1 | 92.2% |
| 3 | 86.3% |
| 5 | 81.1% |
| 8 | 73.9% |
So if you hit 5 reps at RPE 8 with 120kg, that puts your 1RM at roughly 120 ÷ 0.811 ≈ 148kg. The calculator works both directions: “Weight → 1RM” estimates your max from a top set, and “1RM → Weight” tells you what to load for a given rep/RPE target, which is handy for autoregulated programs that prescribe things like “3 reps @ RPE 7.”
RPE vs percentage-based training
Fixed percentages assume your 1RM is constant and that you know it precisely. In reality your readiness shifts day to day with sleep, stress, and fatigue from your last session. RPE-based programming adjusts for that automatically: RPE 8 lands on a heavier weight on a good day than on a tired one.
The catch is that RPE depends on your own judgment, and that takes practice to get right. Most intermediate and advanced programs end up blending both: percentages for accessory and volume work, RPE for top sets.
FAQ
What does RPE 8 mean in weightlifting?
It means you had about 2 more reps left in good form before failure, or RIR 2. RPE 10 is the other end of the scale: an all-out set with nothing left.
What’s the difference between RPE and RIR?
Same scale, opposite directions. RIR (Reps in Reserve) counts how many more reps you could’ve done. RPE turns that into a 1-10 effort rating: RPE 10 = RIR 0, RPE 9 = RIR 1, RPE 8 = RIR 2, and so on.
How accurate is RPE-based training?
Depends how practiced you are at reading your own effort. Lifters who’ve trained near failure a lot tend to rate RPE within about half a point. Beginners usually underestimate how close to failure they actually are, but that gets better with experience.
Should I use RPE or fixed percentages?
Both have their place. Percentages are simple and predictable, good for beginners and accessory work. RPE adapts to how you’re feeling that day, which makes it more useful for top sets once you’re past the beginner stage. Plenty of programs use both at once.
Why does the calculator say my RPE/rep combination "isn't in the table"?
The RTS chart only covers combinations that actually happen. 10 reps at RPE 10, for instance, isn't in there, because almost nobody can judge "zero reps left" at that rep count. Try fewer reps or a slightly higher RPE.
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Want a program built around these numbers? Browse the WOL Library for percentage-based and RPE-based training plans.