Hydraulic Conductivity Calculator

Calculate conductivity using Darcy, constant, or falling head. Convert units and review key steps instantly. Download CSV and PDF to share your findings easily.

Calculator
Choose a method and enter inputs
Reset
Use lab test options for permeameter measurements.
Viscosity supports temperature correction and k calculations.
Kref = Kmeas × (μmeas/μref)
Used to estimate water viscosity at measurement conditions.
Choose a consistent reporting reference.
Only used for custom reference temperature.
Dynamic viscosity at measurement conditions.
Used when correction is enabled.
Tip: match your lab’s reporting standard.
Darcy method inputs
Volumetric flow through the sample.
Length along the flow direction.
Area perpendicular to flow.
Hydraulic head drop across the sample.
Constant-head test inputs
Volume collected at constant head.
Time interval for volume measurement.
Sample length along the flow direction.
Cross-sectional area of the specimen.
Constant head maintained during the test.
Falling-head test inputs
Cross-sectional area of the standpipe.
Cross-sectional area of the specimen.
Length along the flow direction.
Time for the head to drop from h1 to h2.
Starting head at time zero.
Ending head after elapsed time.
Fluid-property relation inputs
Uses K = (k ρ g) / μ
Density at measurement conditions.
Viscosity reminder
This method uses μ at measurement conditions.
Set viscosity source above before calculating.
Intrinsic permeability is medium-only (not fluid-dependent).
Used only when computing k from K.
Useful when you want a fluid-independent parameter.
Used only if the checkbox is enabled.
Tip
Keep units consistent to reduce rounding error.
This calculator converts everything to SI internally.
Example data table
Method Inputs (example) K result (approx.)
Darcy Q=2×10-6 m³/s, L=0.10 m, A=0.00314 m², Δh=0.50 m 1.27×10-4 m/s
Constant-head V=0.50 L, t=120 s, L=10 cm, A=50 cm², h=30 cm 2.78×10-5 m/s
Falling-head a=1.0 cm², A=50 cm², L=10 cm, t=300 s, h1=50 cm, h2=20 cm 5.11×10-6 m/s
Examples are illustrative; your setup and packing conditions may differ.
Formula used
  • Darcy form: K = (Q · L) / (A · Δh)
  • Constant-head test: K = (V · L) / (A · t · h) (since Q=V/t)
  • Falling-head test: K = (a · L / (A · t)) · ln(h1/h2)
  • Fluid-property relation: K = (k · ρ · g) / μ (k is intrinsic permeability)
  • Viscosity correction: Kref = Kmeas · (μmeas / μref) (same porous medium)
How to use this calculator
  1. Pick the method that matches your experiment or field data.
  2. Enter measurements and select correct units for each input.
  3. Choose viscosity source: temperature-based water, or manual values.
  4. Enable correction if you need K reported at a reference condition.
  5. Press Calculate to view results above the form instantly.
  6. Use CSV/PDF buttons to export the displayed results.
Educational use only. Verify against your laboratory standard and instrumentation limits.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.