Perceived Exertion Calculator

The Borg Rate of Perceived Exertion (RPE) scale was developed by Swedish researcher Gunnar Borg and ranges from 6 to 20. The scale is deliberately designed so that multiplying the RPE by 10 gives an approximate heart rate in beats per minute for a healthy adult. So an RPE of 12 corresponds to approximately 120 bpm.

The modified Borg CR10 scale ranges from 0 (rest) to 10 (maximal effort). It is commonly used for rating dyspnoea (breathlessness) and is also used in sports science and clinical settings. A CR10 rating of 5 to 6 corresponds roughly to a 6-20 scale rating of 13 to 15 (somewhat hard).

For healthy adults, the Borg RPE-to-heart-rate relationship (RPE x 10) is reasonably accurate within 10 to 15 bpm. However, the relationship varies with age, fitness level, medication (particularly beta-blockers), heat and humidity, and caffeine intake. Heart rate monitoring is more accurate than RPE for precise intensity control.

ACSM guidelines for aerobic training: very light (RPE 10-11), light (12-13), moderate (13-14), hard (15-16), very hard (17-18), maximal (19-20). For most health and fitness goals, training at RPE 12 to 14 (moderate intensity) for most sessions, with some sessions at 15 to 16 (vigorous), is effective.

RPE can serve as a practical alternative when heart rate monitoring is unavailable or unreliable. Athletes with high body awareness can track training load accurately using RPE. However, for precise intensity zones, altitude training, heat training, or when medications affect heart rate, direct heart rate monitoring is preferable.