▸ processconvert
Permeability

Dtomm²

Convert darcy (D) to square millimetres (permeability) (mm²).

Factor1 D = 9.869233e-7 mm²

Converter

D

Accepts numbers or expressions, e.g. 150 + 14.7

Result
9.86923e-7mm²

Rendered to 6 significant figures.

Formula

Formula
mm² = D × 9.869233e-7

Multiply any value in darcy by 9.869233e-7 to obtain the value in square millimetres (permeability).

Worked example

Convert 1 D to mm².

  1. 01Start with 1 D.
  2. 02Multiply by the conversion factor: 1 × 9.869233e-7 = 9.86923e-7 mm².
Result1 D = 9.86923e-7 mm²

Conversion table

Dmm²
19.8692e-7
21.9738e-6
54.9346e-6
109.8692e-6
201.9738e-5
504.9346e-5
1009.8692e-5
2000.00019738
5000.00049346
10000.00098692

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from D to mm²?
1 D equals 9.869233e-7 mm². To convert, multiply the value in darcy by 9.869233e-7.
How do I convert 1 D to mm²?
1 D = 9.86923e-7 mm². For any value, multiply by 9.869233e-7.
How do I convert mm² back to D?
Divide by the same factor — or equivalently, multiply by 1013250. So 1 mm² = 1.01325e+6 D.
When would I need to convert darcy to square millimetre (permeability)?
Permeability conversions between D and mm² appear in petroleum and reservoir engineering, hydrogeology, geotechnical engineering, packed-bed filtration and porous-materials research. The darcy (D) and its sub-multiples (mD, µD, nD) dominate petroleum-engineering documentation; SI area-equivalent units (m², µm², mm², cm², ft²) appear in geophysics and porous-media research. Intrinsic permeability is a property of the porous medium alone — this category does NOT include hydraulic conductivity (m/s, requires fluid density and viscosity), gas permeability (Klinkenberg slip corrections) or membrane-permeability coefficients, all of which are different physical quantities and require explicit assumptions.
Is the conversion exact?
The factor shown is precise to at least 7 significant figures. For most process-engineering work this is far better than instrument accuracy. For metrology or trade applications, refer to the relevant national standard (NIST, BIPM, ISO 80000).

Related conversions