The current tool is an implementation of Casagrande’s plasticity chart (1948). It is used to classify fine-grained soils using their plasticity characteristics as expressed by the Plasticity Index (IP) and Liquid Limit (LL).

Samples with high plasticity tend to be clay-based materials, samples with low plasticity tend to be silt-based materials, and samples with no plasticity tend to have little or no silt or clay.