RPE Calculator
Convert between RPE, reps, and %1RM. Find the load for "5 @ RPE 8" or back-solve what RPE your set actually was. Free, no signup.
81.1% of your 1RM — the expected intensity for 5 reps at RPE 8.
About this calculator
RPE (Rate of Perceived Exertion) on the 1–10 scale anchors training to effort instead of fixed percentages. RPE 10 = no reps left in the tank; RPE 8 = ~2 reps in reserve; RPE 6 = ~4 reps in reserve. This calculator uses the Reactive Training Systems (RTS) chart — a 2D lookup of RPE × reps → %1RM — to convert in either direction. Use the "Find load" mode when a program prescribes something like "5 @ RPE 8" and you need to know what weight to put on the bar. Use the "Find RPE" mode when you logged a set with a known 1RM and want to know how hard it actually was. The chart is most reliable for 1–6 reps in trained lifters; high-rep sets become more variable because conditioning and pain tolerance start to dominate over pure strength.
Sources
Reactive Training Systems RPE chart (Mike Tuchscherer, 2008). Widely cited in Israetel/RP, Helms, and Nuckols programming guides.
FAQs
How accurate is the RPE chart?
Within roughly 2–3% of true %1RM for trained lifters on compound barbell lifts in the 1–6 rep range. Accuracy drops for higher reps and isolation work — conditioning, pain tolerance, and technique fatigue start to dominate over pure strength. Use the chart as a starting point, then adjust based on your own log.
What does "RPE 8" mean exactly?
RPE is anchored to reps-in-reserve (RIR). RPE 10 = no reps left (true failure). RPE 9 = 1 rep left. RPE 8 = 2 reps left. RPE 7 = 3 reps. Half-step values (8.5, 9.5) interpolate — RPE 8.5 means you might have squeaked out one more rep, maybe two. Below RPE 5 the scale becomes unreliable because the effort is too low to estimate well.
Should I use RPE or fixed percentages?
RPE adapts to your daily readiness — if you’re fatigued, RPE 8 will be lighter than it was last week, and the load self-corrects. Fixed percentages don’t adjust, which can mean hitting a planned 85% on a bad day at RPE 10. Most modern programs blend the two: percentages set the rough zone, RPE caps the actual effort.
Why does the chart stop at 12 reps?
Above 12 reps, %1RM becomes a poor proxy for difficulty — conditioning, work capacity, and tolerance to discomfort matter more than maximal strength. Beyond 12 reps you’re training a different quality (hypertrophy via metabolic stress, work capacity), and the percentage-based lookup is no longer meaningful.