What this calculator does
Hydraulic conductivity (K) describes how easily water moves through a soil or other porous material — a key property in groundwater studies, drainage design, and geotechnical engineering. This calculator estimates K from a constant-head permeameter test.
The formula
Using Darcy’s law, K = (Q × L) / (A × h), where Q is the volumetric flow rate through the sample (volume collected divided by time), L is the length of the sample along the flow path, A is its cross-sectional area, and h is the hydraulic head difference driving the flow.
This calculation assumes laminar (Darcy-compliant) flow, a fully saturated sample, and steady-state conditions typical of a constant-head lab test. Field conditions can vary considerably from lab results. This tool is intended for general educational and preliminary engineering estimation, not a substitute for a certified geotechnical analysis.