Enter penetration and load data to calculate stress values and CBR results automatically.
Standard CBR values are typically taken at 2.5 mm and 5.0 mm penetration. This calculator uses standard reference loads of 13.24 kN at 2.5 mm and 19.96 kN at 5.0 mm.
Point
Penetration (mm)
Load
Stress (MPa)
1
-
2
-
3
-
4
-
5
-
6
-
7
-
Load @ 2.5 mm
-
Interpolated if needed
CBR @ 2.5 mm
-
Based on 13.24 kN
Load @ 5.0 mm
-
Interpolated if needed
Governing CBR
-
Higher of 2.5 / 5.0 mm
Formula used: Stress = Load / Plunger Area and CBR (%) = Test Load / Standard Load × 100.