Compaction Test Calculator

Calculate wet density, dry density, void ratio, and degree of saturation from Proctor compaction test data.

Inputs

Wet Soil Weight

lbs

ASTM D698: standard Proctor; ASTM D1557: modified Proctor (4.5× energy); field spec typically 95% max dry density

Mold Volume

ft³

Moisture Content

ASTM D2216: sandy soil optimum ~10–14%; clay optimum ~15–25%; measure w=(Wwet–Wdry)/Wdry×100

Specific Gravity (Gs)

Tab to move between fields

Results

Dry Density

107.3 pcf

Zero Air Void Density

126.5 pcf

Wet Density120.1 pcf

Degree of Saturation57.5%

Void Ratio (e)0.56

How to Use This Calculator

Enter wet soil weight (lbs) and mold volume (ft³) from your Proctor test sample.
Set measured moisture content (%) and soil specific gravity (Gs).
Review Wet Density, Dry Density (pcf), Degree of Saturation (%), and Void Ratio.
Compare dry density to the Proctor maximum to calculate compaction percentage.

How the result changes with Mold Volume

Mold Volume	Dry Density	Zero Air Void Density
0.02	188 pcf	126.5 pcf
0.04	86.1 pcf	126.5 pcf
0.07	52.1 pcf	126.5 pcf
0.09	39.2 pcf	126.5 pcf

What each input means

Wet Soil Weight: Weight of wet compacted soil specimen per ASTM D698 (Standard Proctor) or ASTM D1557 (Modified Proctor). Standard Proctor: 3-layer, 25 blows/layer; Modified: 5-layer, 25 blows at higher energy for heavy compaction.
Mold Volume: Volume of the compaction mold. Standard Proctor mold is 1/30 ft³ (0.0333 ft³ or 944 cm³).
Moisture Content: Water content of the soil by weight percentage per ASTM D2216, determined by oven-drying at 110°C. Sandy soils: optimal typically 8–14%; clayey soils: 15–25% at Proctor optimum.
Specific Gravity (Gs): Specific gravity of soil solids. Sand ≈ 2.65; clay ≈ 2.70; organic soil ≈ 2.40-2.55.

How this is calculated

Worked example, using the default values

Identify Input Parameters
4 parameters
Wet Soil Weight = 4, Mold Volume = 0.0333, Moisture Content = 12, Specific Gravity (Gs) = 2.68 = 4 input(s) provided
Calculate Dry Density
Dry Density
107.3 = 107.3
Calculate Zero Air Void Density
Zero Air Void Density
126.5 = 126.5
Calculate Wet Density
Wet Density
120.1 = 120.1
Calculate Degree of Saturation
Degree of Saturation
57.5 = 57.5

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