What is the difference between resistance and resistivity?

Resistance (R, in Ω) depends on both the material and the geometry of the sample. Resistivity (ρ, in Ω·m) is a material property independent of geometry: ρ = R × A / L, where A is cross-sectional area and L is length. Two wires of the same material but different lengths and diameters will have different R but the same ρ.

Why is copper's resistivity expressed in μΩ·cm?

Copper's resistivity (1.68 μΩ·cm = 1.68×10⁻⁸ Ω·m) is very small. The μΩ·cm unit keeps the number manageable for metals. In the US, Ω·cmil/ft (ohm·circular-mil per foot) is still used in wire tables: copper ≈ 10.37 Ω·cmil/ft at 20°C.

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Electric Resistivity Converter

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From

Sig. figures:

Sci notation

Ohm·metre

Ω·m

1.680000e-8

Milliohm·metre

mΩ·m

1.680000e-5

Microohm·metre

μΩ·m

0.0168

Nanoohm·metre

nΩ·m

16.8

Picoohm·metre

pΩ·m

16800

Ohm·centimetre

Ω·cm

1.680000e-6

Milliohm·centimetre

mΩ·cm

0.00168

Microohm·centimetre

μΩ·cm

1.68(input)

Nanoohm·centimetre

nΩ·cm

1680

Ohm·inch

Ω·in

6.614173e-7

Ohm·foot

Ω·ft

5.511811e-8

Ohm·cmil per foot

Ω·cmil/ft

10.1057

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Convert electrical resistivity (ρ = R·A/L) across 12 units: SI (Ω·m, mΩ·m, μΩ·m, nΩ·m, pΩ·m), per-cm (Ω·cm, mΩ·cm, μΩ·cm, nΩ·cm), and Imperial (Ω·in, Ω·ft, Ω·cmil/ft). Reference: Cu 1.68×10⁻⁸ Ω·m = 1.68 μΩ·cm; glass 10¹⁰–10¹⁴ Ω·m. Sci notation recommended. 100% browser-based.

How to Use

1Type a resistivity value (e.g. 1.68 for copper in μΩ·cm)
2Select your starting unit (e.g. μΩ·cm, Ω·m, nΩ·m, Ω·cmil/ft)
3Select your target unit - the result appears instantly
4Enable Sci notation (strongly recommended for metal resistivities)
5All 12 conversions appear across SI, Per cm, and Imperial groups
6Hover any row to copy or use as input; click ⇄ to swap
7Open 'Material resistivity reference' for metals, semiconductors, and insulators

Features

12 resistivity units: Ω·m, mΩ·m, μΩ·m, nΩ·m, pΩ·m, Ω·cm, mΩ·cm, μΩ·cm, nΩ·cm, Ω·in, Ω·ft, Ω·cmil/ft
Groups: SI (per metre), Per centimetre, Imperial
Material reference: Cu, Al, Au, Fe, Si, glass
Scientific notation on by default
One-click copy per result
100% browser-based

Electric Resistivity Converter

How to Use

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