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Permeability

mDtomm²

Convert millidarcy (mD) to square millimetres (permeability) (mm²).

Factor1 mD = 9.869233e-10 mm²

Converter

mD

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

Result
9.86923e-10mm²

Rendered to 6 significant figures.

Formula

Formula
mm² = mD × 9.869233e-10

Multiply any value in millidarcy by 9.869233e-10 to obtain the value in square millimetres (permeability).

Worked example

Convert 1 mD to mm².

  1. 01Start with 1 mD.
  2. 02Multiply by the conversion factor: 1 × 9.869233e-10 = 9.86923e-10 mm².
Result1 mD = 9.86923e-10 mm²

Conversion table

mDmm²
19.8692e-10
21.9738e-9
54.9346e-9
109.8692e-9
201.9738e-8
504.9346e-8
1009.8692e-8
2001.9738e-7
5004.9346e-7
10009.8692e-7

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from mD to mm²?
1 mD equals 9.869233e-10 mm². To convert, multiply the value in millidarcy by 9.869233e-10.
How do I convert 1 mD to mm²?
1 mD = 9.86923e-10 mm². For any value, multiply by 9.869233e-10.
How do I convert mm² back to mD?
Divide by the same factor — or equivalently, multiply by 1.01325e+9. So 1 mm² = 1.01325e+9 mD.
When would I need to convert millidarcy to square millimetre (permeability)?
Permeability conversions between mD 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).

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