▸ processconvert
Permeability

mm²toin²

Convert square millimetres (permeability) (mm²) to square inches (permeability) (in²).

Factor1 mm² = 0.001550003 in²

Converter

mm²

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

Result
0.999752in²

Rendered to 6 significant figures.

Formula

Formula
in² = mm² × 0.001550003

Multiply any value in square millimetres (permeability) by 0.001550003 to obtain the value in square inches (permeability).

Worked example

Convert 645 mm² to in².

  1. 01Start with 645 mm².
  2. 02Multiply by the conversion factor: 645 × 0.001550003 = 0.999752 in².
Result645 mm² = 0.999752 in²

Conversion table

mm²in²
10.00155
20.0031
50.00775
100.0155
200.031
500.0775
1000.155
2000.31
5000.775
10001.55

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from mm² to in²?
1 mm² equals 0.001550003 in². To convert, multiply the value in square millimetres (permeability) by 0.001550003.
How do I convert 1 mm² to in²?
1 mm² = 0.00155 in². For any value, multiply by 0.001550003.
How do I convert in² back to mm²?
Divide by the same factor — or equivalently, multiply by 645.16. So 1 in² = 645.16 mm².
When would I need to convert square millimetre (permeability) to square inch (permeability)?
Permeability conversions between mm² and in² 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