Soil plasticity index calculator

Calculate plasticity index and limit consistency flag with your own figures.

Your numbers

Use the units shown. Results update as you change valid inputs.

Use plasticity index and limit consistency flag to compare changes to your inputs. The method and limits below explain the scope.

Examples

Examples

Try the starting example

Liquid limit (%)
45
Plastic limit (%)
25
Plasticity index (percentage points)
20
Limit consistency flag
liquid limit ≥ plastic limit

Try another scenario

Liquid limit (%)
46
Plastic limit (%)
25
Plasticity index (percentage points)
21
Limit consistency flag
liquid limit ≥ plastic limit
Calculation method

Calculation method

Plasticity index (percentage points)

Plasticity index=liquid limit−plastic limit; explicitly flag reversed limits.

Limit consistency flag

Plasticity index=liquid limit−plastic limit; explicitly flag reversed limits.

Symbols and units
a
Liquid limit (%)
b
Plastic limit (%)

Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.

Assumptions & limits

Assumptions & limits

  • User-supplied measurements and assumptions; Plasticity index=liquid limit−plastic limit; explicitly flag reversed limits. Supported limits: Finite numeric values bounded to 1e9 magnitude; lists and tables contain 1–100 records unless a stricter bound is stated. Inputs use the units shown. Lists explicitly paired by a method must have matching lengths; independent polynomial coefficient vectors may differ. Respect stated physical, interpolation, policy and computational domain limits.
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Further reading

Method reference ↗

Background reading; this does not imply endorsement or independent review of SumFizz.

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