About this tool Calculate rock porosity, dry density, and saturated density from laboratory test data. Two methods are supported: the saturation method (using saturated, dry, and submerged masses) and the caliper method (using mass and specimen dimensions).
Porosity and density are fundamental rock properties that control strength, permeability, durability, and weathering resistance. This tool pairs with the existing soil phase relationship calculators but is designed specifically for rock core specimens.
Supports AGS file upload — drag and drop an AGS file to extract data from the RDEN (Rock Density) group. Standards: BS EN 13755, ISRM Suggested Methods for porosity and density determination.
How to use this tool 1. Select the test method — saturation (most accurate) or caliper (quick estimate).
2. Enter specimen masses and dimensions — in grams and millimetres.
3. Or upload an AGS file — RDEN data is extracted automatically.
Technical information n = (Msat - Md) / (Msat - Msub) × 100%
ρd = Md / V where V = (Msat - Msub) / ρw
Typical values: Granite n = 0.5–1.5%, ρd = 2.6–2.7 | Sandstone n = 5–25%, ρd = 2.0–2.6 | Limestone n = 1–20%, ρd = 2.2–2.7 | Chalk n = 20–45%, ρd = 1.4–2.0 Mg/m³
Limitations The saturation method assumes complete saturation of accessible pores. Rocks with very low porosity (<1%) may not fully saturate under vacuum, giving underestimates of porosity.
The caliper method assumes regular geometry and does not distinguish between bulk and effective porosity. It is less accurate than the saturation method for irregular specimens.
Porosity measured on intact rock specimens does not include macro-fracture porosity. Rock mass porosity and permeability are typically much higher than intact rock values.
Revision history 13 October 2026: Initial release
Disclaimer This tool is provided for educational and general information purposes only. It is not a substitute for professional engineering advice, design or verification.
Diggy and its contributors are not licensed engineering consultants and no results generated by this tool should be used directly for construction, design or safety-critical decisions.
All values and outputs are based on published empirical correlations and should be independently checked and confirmed by a qualified geotechnical engineer before use.
By using this tool, you accept full responsibility for how you interpret and apply the information provided.
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