What is the Rock Density Calculator?
Measure rock bulk density from mass and volume with this free rock density calculator. Enter direct mass and volume, rectangular block dimensions (L × W × H), or drill core diameter and length. Optionally compute porosity and void ratio from grain density, and compare results to typical ranges for granite, basalt, limestone, sandstone, and more. Results in g/cm³, kg/m³, or lb/ft³. Runs instantly in your browser with no signup.
How to use the Rock Density Calculator
- Choose sample shape: Mass & Volume, Rectangular Block, Drill Core, or Porosity mode.
- Select metric (g, cm) or imperial (lb, in) units.
- Optionally pick a rock type to compare against typical density ranges.
- Enter mass and dimensions or bulk/grain density for porosity.
- Review bulk density, porosity, void ratio, classification, and calculation steps.
Common use cases
- Calculating bulk density from a diamond drill core in the lab
- Geology homework on porosity of sandstone vs grain density
- Checking whether a granite sample falls in the expected 2.6–2.7 g/cm³ range
- Converting rock sample mass and block dimensions to kg/m³
- Field geotechnical logging alongside soil density measurements
Frequently asked questions
- What is rock bulk density?
- Bulk density is the mass of a rock sample divided by its total volume (including pores and fractures): ρ = m/V. It is reported in g/cm³ (equivalent numerically to Mg/m³) or lb/ft³. Crystalline rocks like granite are typically 2.6–2.8 g/cm³.
- How do I measure density of a drill core?
- Weigh the core (dry), measure diameter and length, and compute volume as V = π(d/2)²L. Bulk density = mass / volume. This calculator performs that calculation with your units.
- What is grain density vs bulk density?
- Grain (matrix) density is the density of the solid mineral material only (~2.65 g/cm³ for quartz). Bulk density includes pore space. Porosity n = (1 − ρ_bulk/ρ_grain) × 100%.
- What density is typical for granite or basalt?
- Granite is typically 2.6–2.7 g/cm³; basalt 2.8–3.0 g/cm³; limestone 2.3–2.7 g/cm³; porous sandstone 2.0–2.6 g/cm³. Select a rock type in the tool to compare your result.
- How is this different from the soil density calculator?
- Soil density handles moisture content and oven-dry/wet masses for unconsolidated material. Rock density focuses on intact rock samples, core geometry, and typical igneous/sedimentary density ranges.
