Darcy (D)
The darcy (D) is the traditional unit of intrinsic permeability, named after Henry Darcy: a medium of 1 D passes 1 cm³/s of a fluid of 1 cP viscosity through 1 cm² under a gradient of 1 atm per cm. It equals 9.869233 × 10⁻¹³ m².
Symbol: D
Quantity: intrinsic permeability of a porous medium
SI relation: 1 D = 9.869233 × 10⁻¹³ m²
Derivation: 1 D passes 1 cm³/s of a 1 cP fluid through 1 cm² under 1 atm/cm: 9.869233 × 10⁻¹³ m².
Exact: no, measured or rounded value
Typical uses
- Oil and gas reservoir permeability
- Aquifer and core analysis
- Filter and porous-media specifications
Convert darcies to other units
| Conversion | 1 D equals | Reverse |
|---|---|---|
| darcy to square metre | 9.869233 × 10⁻¹³ m² | square metre to darcy |
| darcy to millidarcy | 1000 mD | millidarcy to darcy |
| darcy to square micrometre | 0.9869233 µm² | square micrometre to darcy |
| darcy to square centimetre | 9.869233 × 10⁻⁹ cm² | square centimetre to darcy |
Open the Permeability Converter (Darcy, Millidarcy, m²) to convert any value between all units.
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "darcy".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Darcy (D). Retrieved October 29, 2026, from https://scientificconverters.com/units/darcy/
IEEE
Scientific Converters, "Darcy (D)," scientificconverters.com. Accessed: Oct. 29, 2026. [Online]. Available: https://scientificconverters.com/units/darcy/