in²tocm²

1 in² equals 6.4516 cm². To convert, multiply the value in square inches (permeability) by 6.4516.

1 in² = 6.4516 cm². For any value, multiply by 6.4516.

Divide by the same factor — or equivalently, multiply by 0.1550003. So 1 cm² = 0.155 in².

Permeability conversions between in² and cm² 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.

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).