Rock Mass Rating Calculator
Calculate Rock Mass Rating (RMR) based on Bieniawski's classification system using uniaxial compressive strength, Rock Quality Designation (RQD), joint spacing, joint condition, and groundwater conditions.
Published by:
isCalculator Editorial Team
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How to use this tool?
Rock Mass Rating (RMR) Calculator – Quick Guide
This calculator computes the RMR value based on five parameters. All inputs must be in metric units (MPa for strength, mm for spacing, % for RQD).
- Enter Uniaxial Compressive Strength (MPa) – e.g., 100. Rating 0–15.
- Enter RQD (%) – between 0 and 100. Rating 3–20.
- Enter Joint Spacing (mm) – e.g., 200. Must be >0. Rating 5–20.
- Select Joint Condition – choose the best description. Rating 0–30.
- Select Groundwater Condition – from dry to flowing. Rating 0–15.
- Click “Calculate RMR” – the total RMR (0–100) and class (I–V) appear below, with a rating breakdown.
Tip: If you see an error, ensure all fields are filled with valid numbers (no negatives, spacing >0, RQD ≤100).
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Frequently Asked Questions
Rock Mass Rating (RMR) is a geomechanical classification system developed by Bieniawski to assess the quality of rock masses for engineering purposes such as tunneling, mining, and slope stability.
RMR uses five parameters: uniaxial compressive strength of intact rock (UCS), Rock Quality Designation (RQD), joint spacing, joint condition, and groundwater conditions.
RMR values range from 0 to 100. Classes: I (81-100) Very good, II (61-80) Good, III (41-60) Fair, IV (21-40) Poor, V (0-20) Very poor.