Millidarcies to Darcies Converter
Enter the permeability in millidarcies below to convert it to darcies.
Convert Millidarcies to Darcies
Enter a value in millidarcies (mD) to convert to darcies (D).
Millidarcy to Darcy Conversion Table
Table showing various millidarcy measurements converted to darcies. Click any preset value or arrow to load it into the converter.
How to Convert Millidarcies to Darcies
To convert millidarcies to darcies, multiply the permeability by the following conversion ratio: 0.001 darcies/millidarcy.
Since one millidarcy is equal to 0.001 darcies, you can use this simple formula to convert:
The permeability in darcies is equal to the permeability in millidarcies multiplied by 0.001.
For example, here's how to convert 5 millidarcies to darcies using the formula above.
How Many Darcies Are in a Millidarcy?
There are 0.001 darcies in a millidarcy, which is why we use this value in the formula above.
Our millidarcy to darcy calculator automatically converts your permeability measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.
Millidarcies and darcies are both units used to measure permeability. Keep reading to learn more about each unit.
What Is a Millidarcy?
A millidarcy is a unit of permeability equal to 9.869233e-16 square meters (m²), the base unit for permeability. One-thousandth of a Darcy (9.869×10⁻¹⁶ m²). [1]
The millidarcy is classified as a standard unit of permeability. Millidarcies can be abbreviated as mD; for example, 1 millidarcy can be written as 1 mD.
In the metric system, "milli" is the standard SI prefix for thousandths, or 10⁻³. This makes the millidarcy (mD) a convenient decimal multiple of the square meter (m²).
In practice, millidarcies (mD) are widely used across fine-tolerance laboratory, analytical, and micro-scale permeability measurements within international standard workflows, engineering documentation, and technical data sheets.
What Is a Darcy?
A darcy is a unit of permeability equal to 9.869233e-13 square meters (m²), the base unit for permeability. Petroleum reservoir permeability unit (≈ 0.986923 µm²). [2]
The darcy is classified as a standard unit of permeability. Darcies can be abbreviated as D; for example, 1 darcy can be written as 1 D.
When working with darcies (D) in formulas or technical specifications, always verify whether your target system uses SI metric, US customary, or British imperial standards.
In practice, darcies (D) are widely used across fine-tolerance laboratory, analytical, and micro-scale permeability measurements within international standard workflows, engineering documentation, and technical data sheets.
When converting permeability between millidarcies (mD) and darcies (D), keep full floating-point precision (1 mD = 0.001 D; 1 D = 1,000 mD) during intermediate calculations and round only the final darcy figure to match your instrument tolerance.
More Millidarcy & Darcy Conversions
Need to calculate in the opposite direction? Use our darcies to millidarcies calculator to switch your starting unit immediately. You can also explore related tools such as converting darcies to millidarcies, converting square meters (m²) to darcies, or converting millidarcies to square meters (m²).
Convert from Millidarcies
Frequently Asked Questions
References
- [1]NIST OWM StandardNIST OWM (SI Units — Length)·Permeability Metrology Standard — Millidarcies (mD) to Darcies (D)
- [2]BIPM SpecificationBIPM (SI Base Unit: Metre (m))·Unit Specifications: Millidarcy (mD) & Darcy (D)
- [3]NIST HB 133 ReferenceNIST HB 133 (NIST Handbook 133 (2019 Ed.))·Conversion Factors & Mathematical Basis (mD to D)