Convert Darcies to Square Micrometres (D to um2)

Formula

µm² = D × 0.9869233

or µm² = D ÷ 1.013249965828

Derivation from SI units:

• 1 D passes 1 cm³/s of a 1 cP fluid through 1 cm² under 1 atm/cm: 9.869233 × 10⁻¹³ m².
• 1 µm² = 10⁻¹² m², almost exactly one darcy (1 D = 0.9869 µm²).
• 1 D = 9.869233 × 10⁻¹³ m² ÷ 1 × 10⁻¹² m² per µm² = 0.9869233 µm²

One unit is a measured value, so the factor is approximate. Darcy definition: darcy; Square Micrometre definition: square micrometre.

Worked examples

1. 1 D is 0.9869233 µm².
   1 D × 0.9869233 = 0.9869233 µm²
2. A sand pack of 2.5 D is 2.46730825 µm².
   2.5 D × 0.9869233 = 2.46730825 µm²

Where it's used

Darcies are converted to square micrometres, the SI-friendly unit that is almost the same size, for reservoir reports in SI.

Darcy to other intrinsic permeability units

Frequently asked questions

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".
• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 4 (derived units) and Table 8 (non-SI units accepted for use with the SI).

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.