Permeability is a measure of the ability of a porous material (typically rock) to allow fluids to pass through it. It is a critical property in petroleum engineering, hydrogeology, geology, and materials science. The standard unit is the Darcy (D), named after French engineer Henry Darcy who formulated Darcy's Law in 1856. Permeability depends on pore size, connectivity, and tortuosity of the porous medium.
Petroleum Permeability
Convert between Darcy, millidarcy, microdarcy, and nanodarcy — the standard units used in petroleum engineering and reservoir characterization.
Conversion Formula
1 Darcy = 1000 millidarcy
Common Conversions
Quick reference table| From | To | Result |
|---|
How to Use This Converter
Our permeability converter is engineered for petroleum engineers, geologists, physicists, and researchers. Follow these steps for accurate conversions.
-
Select a Category Choose from 6 categories: Petroleum, SI Units, Imperial, Scientific (Barn), Land, and Regional.
-
Choose Source Unit Pick the unit you want to convert from (e.g., Darcy, millidarcy, square meter, barn).
-
Choose Target Unit Select the unit you want to convert to from the second dropdown.
-
Enter Value Type your permeability value — the result appears instantly as you type.
-
Swap Units Click the swap button to instantly reverse the conversion direction.
-
View Formula The exact conversion formula is displayed below for verification and documentation.
Why Professionals Choose ASLI FORM
Built with precision engineering and premium design, our permeability converter meets the demands of petroleum engineers, geologists, and researchers worldwide.
-
Scientific Precision Results accurate to 10 significant digits using NIST and SPE-standard conversion factors.
-
Instant Results Real-time conversion as you type — no buttons to click, no waiting.
-
Works Offline All calculations run locally in your browser. Perfect for field work and remote locations.
-
Universal Compatibility From basic keypad phones to 4K displays — works on every device and operating system.
-
Zero Tracking No cookies, no analytics, no data collection. Your research data is completely private.
-
Free Forever No subscriptions, no hidden fees, no usage limits, no advertisements.
Frequently Asked Questions
A Darcy (D) is defined as the permeability that allows a fluid of 1 centipoise viscosity to flow at a rate of 1 cm³/s through a cross-sectional area of 1 cm² under a pressure gradient of 1 atmosphere per centimeter. Mathematically: 1 Darcy = 0.986923 × 10⁻¹² m². In practice, the millidarcy (mD) is most commonly used since most reservoir rocks have permeability in the 1-1000 mD range.
A millidarcy (mD) is one-thousandth of a Darcy. The relationship is: 1 Darcy = 1000 millidarcies. Since most reservoir rocks have permeability values between 1-1000 mD, the millidarcy is the most practical unit for petroleum engineering. For example, a good reservoir rock might have 100-500 mD permeability, while tight formations may have less than 1 mD.
A barn (b) is a unit of area used primarily in nuclear physics, equal to 10⁻²⁸ square meters. The name comes from the phrase "big as a barn" because it seemed large compared to typical nuclear cross-sections. While not commonly used for rock permeability, barns appear in molecular and atomic-scale permeability calculations, neutron scattering experiments, and particle physics. Submultiples include millibarn (mb), microbarn (μb), nanobarn (nb), picobarn (pb), and femtobarn (fb).
The conversion factor is: 1 Darcy = 0.986923 × 10⁻¹² m² (approximately 10⁻¹² m²). To convert from Darcy to square meters, multiply by 0.986923 × 10⁻¹². To convert from square meters to Darcy, divide by 0.986923 × 10⁻¹² (or multiply by approximately 1.01325 × 10¹²). Our converter handles these calculations automatically with 10-digit precision.
Typical permeability ranges (in millidarcy):
- Gravel: 100,000+ mD (very high)
- Sandstone (good reservoir): 100-1000 mD
- Sandstone (average): 10-100 mD
- Limestone: 1-100 mD
- Tight gas sand: 0.001-0.1 mD
- Shale: 0.0001-0.001 mD (very low)
- Granite (intact): 0.000001 mD (essentially impermeable)
Yes, the ASLI FORM Permeability Converter is 100% free forever. There are no registration requirements, no usage limits, no subscription fees, and no hidden charges. We do not display advertisements and we do not collect any personal data. Our mission is to provide a premium tool that engineers, researchers, and students worldwide can use without barriers.
Yes. Once the page loads, all calculations happen locally in your browser. There is no server-side processing, no API calls, and no internet dependency for conversions. This makes the tool perfect for field work at drilling sites, remote laboratories, offshore platforms, and anywhere connectivity is limited or unavailable.
Our converter delivers results accurate to 10 significant digits using conversion factors from official metrology institutes including NIST, SPE (Society of Petroleum Engineers), and the International Bureau of Weights and Measures (BIPM). This level of precision is suitable for engineering calculations, scientific research, academic work, and professional petroleum engineering applications.
These are traditional Indian land measurement units that vary by region:
- Bigha: Varies from 1,600 to 6,771 sq meters depending on state (Assam, Bihar, Rajasthan, etc.)
- Guntha (or Gunta): Approximately 101.17 sq meters, used in Maharashtra, Karnataka, and other states
- Marla: Approximately 25.29 sq meters, used in Punjab, Haryana, and Himachal Pradesh
- Kanal: 20 Marlas = approximately 505.86 sq meters
Absolutely. Our converter is designed with a mobile-first responsive approach and works perfectly on every device — from basic keypad phones to 4K desktop displays. The interface adapts intelligently: desktops get a sidebar, tablets get a collapsible sidebar, and mobile devices get optimized dropdowns. Touch interactions, scroll snapping, and momentum scrolling are all optimized for mobile use in the field.
Several key features set us apart:
- Premium design with sidebar navigation and fluid animations
- Real-time conversion — no submit button needed
- Formula explanations for educational and documentation value
- Common conversions table for quick reference in the field
- Offline capability for field work at remote sites
- Zero tracking — complete privacy for sensitive research data
- Universal compatibility across all devices and operating systems
- 40+ units covering petroleum, SI, Imperial, scientific, and regional units
Need More Professional Tools?
Explore our complete suite of 150+ free tools including calculators, converters, PDF tools, code editors, and AI-powered utilities for engineers and researchers.