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Permeability

mm²tomD

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

Factor1 mm² = 1.01325e+9 mD

Converter

mm²

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

Result
1.01325e+9mD

Rendered to 6 significant figures.

Formula

Formula
mD = mm² × 1.01325e+9

Multiply any value in square millimetres (permeability) by 1.01325e+9 to obtain the value in millidarcy.

Worked example

Convert 1 mm² to mD.

  1. 01Start with 1 mm².
  2. 02Multiply by the conversion factor: 1 × 1.01325e+9 = 1.01325e+9 mD.
Result1 mm² = 1.01325e+9 mD

Conversion table

mm²mD
11.0132e+9
22.0265e+9
55.0662e+9
101.0132e+10
202.0265e+10
505.0662e+10
1001.0132e+11
2002.0265e+11
5005.0662e+11
10001.0132e+12

Reference values rounded to 5 significant figures for display.

FAQ

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