Convert Circular Mil Ohm/Foot to Ohm Centimeters
Circular Mil Ohm/Foot (cmil·Ω/ft) to Ohm Centimeter (Ω·cm) electric resistivity conversion — enter any value below to get an instant result, or use the table for common values.
Results from this calculator are estimates provided for general informational purposes only, based on formulas, rates, and standards commonly accepted as of 2026. Figures may differ slightly from other calculators or professional sources due to rounding methods, differing assumptions, or regional regulations, and rules may change over time. Always consult a qualified professional — such as a financial advisor, healthcare provider, or other relevant specialist — before making decisions based on these results.
Result
1 cmil·Ω/ft = 1.66243E-07 Ω·cm
1 Circular Mil Ohm/Foot = 1.66243E-07 Ohm Centimeters
1 Ohm Centimeter = 6015304.9 Circular Mil Ohm/Foot
1 cmil·Ω/ft in every supported unit
Conversion chart: Circular Mil Ohm/Foot to Ohm Centimeters
Conversion table
| Circular Mil Ohm/Foot (cmil·Ω/ft) | Ohm Centimeter (Ω·cm) |
|---|---|
| 0.01 cmil·Ω/ft | 1.66243E-09 Ω·cm |
| 0.1 cmil·Ω/ft | 1.66243E-08 Ω·cm |
| 1 cmil·Ω/ft | 1.66243E-07 Ω·cm |
| 2 cmil·Ω/ft | 3.32485E-07 Ω·cm |
| 3 cmil·Ω/ft | 4.98728E-07 Ω·cm |
| 5 cmil·Ω/ft | 8.31213E-07 Ω·cm |
| 10 cmil·Ω/ft | 1.66243E-06 Ω·cm |
| 20 cmil·Ω/ft | 3.32485E-06 Ω·cm |
| 50 cmil·Ω/ft | 8.31213E-06 Ω·cm |
| 100 cmil·Ω/ft | 1.66243E-05 Ω·cm |
| 1000 cmil·Ω/ft | 0.00016624261 Ω·cm |
Circular Mil Ohm/Foot (cmil·Ω/ft)
Definition: A resistivity unit unique to the American wire industry, expressing resistivity as ohms per foot of length per circular mil of cross-sectional area — the circular mil being the standard US unit for wire cross-section (the area of a circle one mil, or 0.001 inch, in diameter).
History: It developed directly out of the American Wire Gauge (AWG) system, where wire cross-sections are conventionally measured in circular mils rather than square millimeters, so expressing resistivity in matching units let engineers compute a wire's resistance directly from its AWG size and length without an extra area-unit conversion step.
Current use: Still the standard resistivity unit in US wire and cable engineering and National Electrical Code ampacity tables — copper's resistivity is commonly quoted as about 10.66 Ω·cmil/ft at 20°C.
Ohm Centimeter (Ω·cm)
Definition: A resistivity unit that substitutes the centimeter for the meter as the reference length, making the numeric value 100 times larger than the equivalent ohm-meter figure for the same physical material.
History: It arose from the CGS-adjacent convention of measuring resistivity in centimeters, which persisted in materials science and especially the semiconductor industry long after the meter became the SI-preferred length unit elsewhere.
Current use: The de facto standard unit for specifying silicon and other semiconductor wafer resistivity in the electronics industry — wafer suppliers and doping specifications are almost always quoted in Ω·cm.
Supported Units
| Unit | Symbol | In Ohm Meter |
|---|---|---|
| Ohm Meter | Ω·m | 1 Ω·m |
| Ohm Centimeter | Ω·cm | 0.01 Ω·m |
| Ohm Inch | Ω·in | 0.0254 Ω·m |
| Microhm Centimeter | μΩ·cm | 1E-08 Ω·m |
| Microhm Inch | μΩ·in | 2.54E-08 Ω·m |
| Abohm Centimeter | abΩ·cm | 1E-11 Ω·m |
| Statohm Centimeter | statΩ·cm | 8.98755E+09 Ω·m |
| Circular Mil Ohm/Foot | cmil·Ω/ft | 1.66243E-09 Ω·m |
About These Parameters
- Value
- The electric resistivity value you want to convert, expressed in the "From" unit. Accepts decimals, and can represent anything from a metal's resistivity in microhm-centimeters to a semiconductor's resistivity in ohm-centimeters.
- From Unit
- The unit your input value is currently measured in — a wafer datasheet's ohm-centimeter rating, a wire table's circular-mil-ohm-per-foot figure, or an older CGS unit like abohm-centimeter or statohm-centimeter.
- To Unit
- The unit you want the result converted into. Use the swap button to flip From and To instantly, which is handy when moving a material spec into the units used in your own design calculations.
How Electric Resistivity Conversion Works
The Formula
Every unit here is defined by a fixed multiplier relative to the ohm-meter. To convert a value from one unit to another:
result = value × (factor of "From" unit ÷ factor of "To" unit)
For Circular Mil Ohm/Foot → Ohm Centimeter: multiply by 1.66243E-07. For example, 1 cmil·Ω/ft × 1.66243E-07 = 1.66243E-07 Ω·cm.
Resistivity vs. Resistance
Resistance (in ohms) tells you how much a specific object opposes current, but that number depends on the object's length and cross-sectional area as much as it depends on what it's made of — double a wire's length and its resistance doubles; double its cross-section and resistance halves. Resistivity strips geometry out of the equation entirely, describing only the material itself: copper is always about 1.68×10⁻⁸ Ω·m regardless of whether it's a hair-thin wire or a thick busbar. That makes resistivity the number engineers actually compare when choosing between materials, while resistance is what they calculate afterward once a specific shape is chosen.
Why So Many Length-Based Variants
Because resistivity is measured "per unit length" in some form, every length unit in common engineering use has spawned its own resistivity unit: centimeters gave the semiconductor industry ohm-centimeter and metallurgy microhm-centimeter, inches gave American manufacturing ohm-inch and microhm-inch, and the circular mil — the standard cross-sectional-area unit for American Wire Gauge tables — combined with the foot to give wire engineers circular-mil-ohm-per- foot, a unit that lets them compute a wire's resistance directly from its AWG size without an extra area conversion. The CGS-era abohm-centimeter and statohm-centimeter round out the list as relics of 19th-century electromagnetic and electrostatic unit systems.
Example
An electric resistivity of 1 cmil·Ω/ft equals 1.66243E-07 Ω·cm. For scale, copper's resistivity is about 1.68×10⁻⁸ Ω·m (1.68 μΩ·cm), a typical doped silicon wafer for integrated circuits might run anywhere from about 0.001 to 100 Ω·cm depending on doping level, and a good electrical insulator like glass can exceed 10¹² Ω·m.
Frequently Asked Questions
How many Ohm Centimeters are in 1 Circular Mil Ohm/Foot?
1 Circular Mil Ohm/Foot (cmil·Ω/ft) equals exactly 1.66243E-07 Ohm Centimeters (Ω·cm).
What's the difference between resistivity and resistance?
Resistivity (ohm-meters) is a property of the material alone, unaffected by shape or size. Resistance (ohms) is the property of one specific object, and depends on that material's resistivity plus the object's length and cross-sectional area. See the separate Electric Resistance Converter for that quantity.
Why do semiconductor datasheets use ohm-centimeters instead of ohm-meters?
Silicon wafer resistivity values typically fall in a range — roughly 0.001 to 100 ohm-centimeters — that reads more naturally in centimeters than in the much smaller numbers meters would produce. The convention stuck from the CGS era and remains the semiconductor industry standard today, even though the rest of SI has moved to meters.
What is a circular mil, and why does wire resistivity use it?
A circular mil is the area of a circle exactly one mil (0.001 inch) in diameter — the standard cross-sectional-area unit used throughout the American Wire Gauge (AWG) system. Expressing wire resistivity in ohms per circular mil per foot lets engineers compute a wire's resistance straight from its AWG size and length, without a separate step to convert circular mils into square inches or square millimeters first.
Are abohm-centimeter and statohm-centimeter still used?
Almost never in modern engineering. They're the resistivity units of the 19th-century CGS electromagnetic (EMU) and electrostatic (ESU) systems respectively, and survive mainly in historical physics literature and theoretical derivations written in Gaussian units, well before the SI's ohm-meter became the near-universal standard.