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Soil Void Ratio Calculator

Compute a soil's void ratio from its specific gravity and dry unit weight.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax

Void ratio

0.58 (e)

High confidence
Equivalent porosity
36.53 %

With the figures above, the void ratio comes to 0.58 (e). This is calculated for United States and cites IRC 2024. Building in another market? Change the selector above so the units and code reference follow.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Standard soil phase relationship: void ratio e = (Gs x γw / γd) − 1, where Gs is specific gravity of solids, γw is the unit weight of water, and γd is the soil's dry unit weight

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Frequently asked questions

What does void ratio represent?
It's the ratio of void (air/water) volume to solid particle volume in a soil sample — a lower void ratio generally means denser, less compressible soil.
Why is this different from porosity?
Void ratio compares void volume to SOLID volume; porosity compares void volume to TOTAL volume — they describe the same underlying void space but as different ratios, and are directly convertible into each other.
How is void ratio used in practice?
It's a key input for consolidation settlement calculations, relative density (for granular soils), and general soil classification and compaction assessment.