By Zencalcy Editorial TeamLast reviewed About us
The Borg RPE scale rates how hard exercise feels on a scale from 6 to 20. It is a quick way to judge intensity without any equipment, and the classic rule of thumb is that the score times ten approximates your heart rate in beats per minute.
Turn a Borg RPE score into an effort level and rough heart rate.
% HRmax ≈ RPE × 5 Approximate heart rate (bpm) ≈ RPE × 10
The Borg scale was built so that RPE times ten approximates heart rate in beats per minute for a healthy adult, against a nominal maximum near 200 bpm. Read as a share of maximum, that is about RPE times five percent. It is an approximation and varies by person and by day.
| Symbol | Meaning |
|---|---|
| RPE | Your rating of perceived exertion on the Borg 6 to 20 scale. |
An RPE of 15 reads as about 75 percent of maximum heart rate and roughly 150 bpm, which the scale labels hard. An RPE of 9 reads as about 45 percent and roughly 90 bpm, a very light effort.
The rating of perceived exertion, or RPE, asks how hard the work feels on a numbered scale. The original Borg scale runs from 6 to 20, chosen so that multiplying the rating by ten approximates heart rate for many people, so a rating of 13 sits near 130 beats per minute. A later version, the CR10, runs from 0 to 10 with verbal anchors from nothing at all to maximal.
RPE works because effort is a real bodily signal, not just a feeling. Breathing rate, muscle noise, and the sense of strain all rise with intensity, so a person can report them without any equipment. The numbers are subjective, but when used consistently by the same person they track physiological load closely.
RPE is valuable when heart rate is unreliable, such as in heat, when dehydrated, or during short intervals where the pulse lags behind the effort. It also captures fatigue and stress that a heart rate monitor cannot see, which is why coaches often pair the two. The key is to anchor the scale to your own sensations and use the same meaning each time.
Continue with the Resting Heart Rate Calculator, Target Heart Rate Calculator, or the TRIMP Calculator — or browse more heart rate & performance tools and all sports calculators.
Judge the whole feeling of the effort: breathing, sweat, and how heavy the legs feel. Let the number come from the sensation rather than from any reading on a screen.
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Last reviewed: September 2026. See how we build and check every tool on the about page.
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Content updated: September 2026