Enter soil test details
The calculator uses wet and dry mass with measured sample volume to estimate wet bulk density, dry bulk density, moisture, porosity, and compaction indicators.
Example data table
These example values show how multiple soil samples can be reviewed during field checks and quality control reporting.
| Sample | Wet Mass + Container (g) | Dry Mass + Container (g) | Tare (g) | Volume (cm³) | Wet Density (kg/m³) | Dry Density (kg/m³) | Moisture (%) |
|---|---|---|---|---|---|---|---|
| A-01 | 1640 | 1505 | 240 | 942.48 | 1485.44 | 1342.20 | 10.67 |
| A-02 | 1760 | 1600 | 240 | 942.48 | 1612.76 | 1440.37 | 11.76 |
| A-03 | 1930 | 1740 | 240 | 942.48 | 1793.13 | 1591.55 | 12.67 |
Formula used
1) Wet soil mass
Mwet soil = Mwet total - Mtare
2) Dry soil mass
Mdry soil = Mdry total - Mtare
3) Core volume
V = π × (D² / 4) × H
4) Wet bulk density
ρwet = Mwet soil / V
5) Dry bulk density
ρdry = Mdry soil / V
6) Moisture content
w = [(Mwet soil - Mdry soil) / Mdry soil] × 100
7) Porosity and void ratio
n = [1 - (ρdry / ρs)] × 100
e = (ρs / ρdry) - 1
8) Relative compaction
RC = (ρdry / MDD) × 100
How to use this calculator
- Choose the volume method that matches your test procedure.
- Enter wet mass, dry mass, and empty container mass.
- For core tests, enter diameter and height with units.
- For sand cone or direct methods, enter the measured volume.
- Add particle density if you want porosity and void ratio.
- Add maximum dry density to evaluate relative compaction.
- Pick your preferred display unit and press calculate.
- Review the result cards, graph, summary table, and exports.
FAQs
1) What is soil bulk density?
Soil bulk density is the mass of soil divided by its total volume. The volume includes solids and pore spaces, making it useful for compaction and field quality assessment.
2) Why calculate both wet and dry bulk density?
Wet bulk density reflects field condition at sampling time. Dry bulk density removes the water effect and is better for comparing compaction levels between different locations and dates.
3) When should I use the core cutter method?
Use the core cutter method when the soil can be sampled with a cylindrical core and the dimensions are known accurately. It works well for many cohesive or fine-grained soils.
4) What does relative compaction tell me?
Relative compaction compares field dry density with laboratory maximum dry density. Higher percentages usually indicate better field compaction, subject to the project specification and test standard.
5) Why is particle density optional?
Particle density is only needed for derived values such as porosity and void ratio. The core bulk density calculations need mass and volume, so the calculator can work without it.
6) Can this tool help with moisture control?
Yes. The moisture content result and optimum moisture comparison help you see whether the sample is wetter or drier than the target compaction condition.
7) Why is unit consistency important?
Mixed units can distort the result immediately. This tool converts units internally, but you still need to enter each measurement in the correct field and choose the correct unit.
8) Is a higher bulk density always better?
Not always. Acceptable density depends on soil type, moisture, design intent, and project requirements. Excessive density can also affect permeability, rooting, or other performance needs.