🪨 Rock Mass Rating (RMR) Calculator

Geotechnical Classification • Stability • Support Guidance

Basic Advanced

Basic RMR Inputs

RMR Classification (Bieniawski)
• 81–100 → Class I (Very Good Rock)
• 61–80 → Class II (Good Rock)
• 41–60 → Class III (Fair Rock)
• 21–40 → Class IV (Poor Rock)
• < 20 → Class V (Very Poor Rock)