Enter the Standard Penetration Test value and the Conversion Factor into the calculator to determine the Bearing Capacity. This calculator can also evaluate any of the variables given the others are known.

Spt To Bearing Capacity Formula

The following formula is used to calculate the Spt To Bearing Capacity.



  • BC is the Bearing Capacity (kN/m²)
  • SPT is the Standard Penetration Test value (blows/30cm)
  • CF is the Conversion Factor (kN/m²/blow)

To calculate the Spt To Bearing Capacity, multiply the Standard Penetration Test value by the Conversion Factor. The result will give the bearing capacity of the soil in kilonewtons per square meter (kN/m²). The Conversion Factor is a constant that varies depending on the type of soil and the specific conditions of the test. It is usually determined through empirical correlations or laboratory tests.

What is Spt To Bearing Capacity?

Spt To Bearing Capacity refers to the process of determining the bearing capacity of soil using the Standard Penetration Test (SPT). The SPT is a common in-situ testing method used to estimate the geotechnical properties of soil. The test provides a measure of the resistance of the soil to penetration, which can be used to estimate its bearing capacity – the ability of the soil to support the loads applied to the ground. The higher the SPT value, the greater the soil’s bearing capacity.

How to Calculate Spt To Bearing Capacity?

The following steps outline how to calculate the Spt To Bearing Capacity:

  1. First, determine the Standard Penetration Test value (SPT) (blows/30cm).
  2. Next, determine the Conversion Factor (CF) (kN/m²/blow).
  3. Next, gather the formula from above = BC = SPT * CF.
  4. Finally, calculate the Bearing Capacity (BC).
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Standard Penetration Test value (SPT) (blows/30cm) = 10

Conversion Factor (CF) (kN/m²/blow) = 5