Electrical Resistivity Converter

Electrical resistivity (ρ) is how strongly a material opposes electric current, whatever the size of the piece. Its SI unit is the ohm-meter (Ω·m). A wire's resistance follows from it: R = ρ * L / A, for a length L and a cross-section A.

Metals are quoted in µΩ·cm: copper is about 1.68 µΩ·cm and aluminium about 2.65. Seawater is about 0.2 Ω·m, and glass 10¹⁰ to 10¹⁴ Ω·m.

How to convert resistivity units

Type a value into any field, and every other unit is calculated at once. Between the two most common units:

• Ω·m to Ω·cm: multiply by 100, since 1 m = 100 cm.
• Ω·cm to Ω·m: divide by 100.

For example, copper's 1.68 µΩ·cm:

1. In Ω·m: divide by 100,000,000.

   1.68 / 100,000,000 = 1.68 × 10⁻⁸ Ω·m

2. In Ω·cmil/ft, the unit of US wire tables:

   1.68 µΩ·cm = 10.11 Ω·cmil/ft

Common conversions

Electrical resistivity units

• Ohm-meter (Ω•m): The Ohm-meter is the standard unit of electric resistivity in the International System of Units (SI). It represents the resistance between opposite faces of a one-meter cube of the material.
  Conversion Factor: 1 Ω•m = 1 Ω•m (Base Unit)

• Ohm-centimeter (Ω•cm): The Ohm-centimeter is another common unit of electric resistivity. It represents the resistance between opposite faces of a one-centimeter cube of the material.
  Conversion Factor: 1 Ω•cm = 0.01 Ω•m

• Ohm-inch (Ω•in): The Ohm-inch is used primarily in the United States and represents the resistance between opposite faces of a one-inch cube of the material. To convert from Ohm-meter to Ohm-inch, use the conversion factor:
  Conversion Factor: 1 Ω•in = 0.0254 Ω•m

• Microohm-centimeter (μΩ•cm): The Microohm-centimeter is a smaller unit used to express very low resistivity values.
  Conversion Factor: 1 μΩ•cm = 1 / 100,000,000 Ω•m = 10^-8 Ω•m

• Microohm-inch (μΩ•in): The Microohm-inch is the corresponding unit to Microohm-centimeter, but in inches.
  Conversion Factor: 1 μΩ•in = 2.54 / 100,000,000 Ω•m = 2.54 * 10^-8 Ω•m

• Abohm-centimeter (abΩ•cm): The Abohm-centimeter is an older unit used in the centimeter-gram-second (CGS) system. One Abohm-centimeter is the equivalent of 10^-9 ohm-centimeters.
  Conversion Factor: 1 abΩ•cm = 10^-11 Ω•m

• Statohm-centimeter (statΩ•cm): The Statohm-centimeter is another unit used in the cgs (centimeter-gram-second) system.
  Conversion Factor: 1 statΩ•cm ≈ 8.988 * 10^11 Ω•cm ≈ 8.988 * 10^9 Ω•m

• Circular-mil-ohm/foot (cmil•Ω/ft): The Circular-mil-ohm per foot is commonly used to measure the resistance of wires and conductors.
  Conversion Factor: 1 cmil•Ω/ft ≈ 1 / 601530493 Ω•m

Frequently asked questions

How do you convert resistivity to conductivity?

Conductivity is the inverse of resistivity: σ = 1 / ρ. A resistivity in Ω·m gives a conductivity in siemens per meter (S/m), so 0.2 Ω·m is 5 S/m. The Electrical Conductivity Converter converts between conductivity units.

Is resistivity the same as resistance?

No. Resistance, in ohms, belongs to one particular piece of material, and depends on its length and thickness. Resistivity, in ohm-meters, belongs to the material itself.