What is the Soil Density Calculator?
Calculate soil bulk density, moisture content, porosity, and void ratio with this free soil density calculator. Enter oven-dry and wet sample masses with volume, or use gravimetric moisture content, or compute porosity from dry bulk and particle density. Results in g/cm³, kg/m³, or lb/ft³ with step-by-step geotechnical formulas. Default particle density 2.65 g/cm³. Runs instantly in your browser with no signup.
How to use the Soil Density Calculator
- Choose From Sample Masses, From Moisture %, or Porosity & Void Ratio.
- Select metric (g, cm³) or imperial (lb, ft³) units.
- Enter wet/dry masses and volume, or moisture %, or dry bulk density.
- Set particle density (default 2.65 g/cm³ for mineral soil) when computing porosity.
- Review dry and wet bulk density, moisture content, porosity, void ratio, and compaction guide.
Common use cases
- Lab analysis of a soil core after oven-drying
- Agronomy and horticulture soil health assessments
- Geotechnical homework on porosity and void ratio
- Estimating dry density when only moisture % and wet mass are known
- Comparing sandy vs compacted clay bulk densities
Frequently asked questions
- What is soil bulk density?
- Bulk density is the mass of dry soil per unit total volume (including pores): γ_dry = m_dry / V. It is usually reported in g/cm³ or Mg/m³ (equivalent to g/cm³ numerically). Typical agricultural topsoil ranges from about 1.0 to 1.6 g/cm³.
- How is moisture content calculated?
- Gravimetric moisture content w = (m_wet − m_dry) / m_dry × 100%. Dry bulk density can also be found from wet density as γ_dry = γ_wet / (1 + w/100).
- What is porosity and void ratio?
- Porosity n = (1 − γ_dry/γ_s) × 100% is the fraction of soil volume that is pores. Void ratio e = γ_s/γ_dry − 1 is pore volume divided by solid volume. Both need particle density γ_s (often 2.65 g/cm³).
- What particle density should I use?
- 2.65 g/cm³ is standard for quartz-dominated mineral soils. Organic soils may use lower values (2.0–2.5). The calculator accepts 2.0–3.0 g/cm³.
- What is a normal dry bulk density?
- Loose topsoil is often 1.0–1.3 g/cm³; compacted clay can exceed 1.6–1.8 g/cm³. Organic and peat soils can be below 0.6 g/cm³. The tool includes a qualitative compaction guide.
