RPE to Percentage Converter
Translate between how hard a set feels (RPE) and a percentage of your one rep max.
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Learn the details
RPE (Rate of Perceived Exertion) maps subjective effort to approximate percentages of your 1RM. RPE 10 is maximal effort, RPE 9 leaves one rep in reserve, RPE 8 leaves two.
RPE usually gets described as how hard a set feels, which is too vague to use. The version worth having counts reps, not feelings. Here is what it measures, when it beats a fixed percentage, and where it lets beginners down.
What RPE really measures
RPE stands for rate of perceived exertion, and in lifting it is anchored to reps in reserve, shortened to RIR: how many more reps you could have completed before failure. RPE 10 means none left, RPE 9 means one, RPE 8 roughly two, RPE 7 about three. Zourdos and colleagues published this RIR-anchored version in 2016, and it is what made the scale specific enough to be worth using. The percentages in the chart above come from Mike Tuchscherer's work.
Why autoregulation exists
A fixed percentage assumes today is an average day. It cannot see that you slept five hours or that you are three weeks into a diet. Seventy five percent is seventy five percent whether the bar feels light or welded to the floor. Autoregulation just means adjusting the load to the lifter in front of you. Told to work at RPE 8, you take a lighter bar on a rough day and a heavier one when things click, and the set does its job either way.
A worked example
With a 315 lb squat, ask for RPE 8 at 5 reps and this tool reads 81.1 percent off the chart, which is 255.5 lbs: five reps that should leave about two in the tank. Run it backwards, telling it you did 250 lbs for 5 against that same 315 max, and it works out 79.4 percent and calls it roughly RPE 7.5. Half a point easier than planned, which is information, not failure.
The honest limitation
Rating your own effort is a skill, and novices are genuinely bad at it. The consistent finding is that less experienced lifters underrate how hard a set was, believing three or four reps are left when one is. It rarely clicks until you have taken a few sets to real failure. Filming helps, since bar speed on the last rep is more honest than memory, but expect your ratings to be rough for a few months.
Using both, not one
Percentages give a plan its spine and RPE keeps it honest, so use both: set the load from a percentage, then let RPE nudge it on the day. That needs a max to work from, which you can estimate from a set you have already done with the one rep max calculator. If you would rather not judge effort yet, a training max bakes the buffer in for you, and the rep range guide covers how many reps belong at that effort.
Sources: Zourdos et al. 2016, RPE and reps in reserve
RPE is a skill, so film your sets to calibrate, and treat RPE 8 (2 reps in reserve) as the sweet spot for most working sets. It lets you push harder on good days and back off on bad ones without leaving the program.