Conductivity to Resistivity Calculator
Enter an electrical conductivity value and the calculator instantly returns the resistivity, or enter a resistivity to get the conductivity. Both directions are live. Choose a preset material to pre-fill the value, pick your preferred units, and see the full worked step alongside a log-scale comparison of where your material sits among common conductors, semiconductors, and insulators.
Formula
Worked example
Copper at 20 C has a conductivity of 5.96 x 10^7 S/m. Resistivity = 1 / (5.96 x 10^7) = 1.68 x 10^-8 ohm.m. Conversely, if you measure a resistivity of 1.68 x 10^-8 ohm.m, conductivity = 1 / (1.68 x 10^-8) = 5.96 x 10^7 S/m.
What are electrical resistivity and conductivity?
Electrical resistivity (rho, symbol rho, unit ohm.m) is an intrinsic material property that measures how strongly a material opposes the flow of electric current. A high resistivity means current is blocked; a low resistivity means current flows easily. Electrical conductivity (sigma, unit S/m) is exactly its reciprocal: sigma = 1 / rho. They carry identical information - one is simply the inverse of the other. Unlike resistance, which depends on the size and shape of an object, resistivity and conductivity are pure material properties that do not change with the dimensions of a sample.
How to convert between conductivity and resistivity
The conversion is a single arithmetic step in either direction. To find resistivity from conductivity, divide 1 by the conductivity: rho (ohm.m) = 1 / sigma (S/m). To find conductivity from resistivity, divide 1 by the resistivity: sigma (S/m) = 1 / rho (ohm.m). For example, copper has a conductivity of about 5.96 x 10^7 S/m, so its resistivity is 1 / (5.96 x 10^7) = 1.68 x 10^-8 ohm.m. The only practical complication is unit consistency: make sure conductivity is in siemens per metre and resistivity is in ohm-metres before applying the reciprocal, then convert the result to any other unit system you need.
Conductors, semiconductors, and insulators
Materials are broadly classified by where their resistivity falls on a log scale spanning roughly 21 orders of magnitude. Metals (conductors) have resistivities below about 10^-6 ohm.m; they conduct because free electrons move through the lattice almost unhindered. Semiconductors (germanium, silicon) fall in the range 10^-6 to 10^3 ohm.m; their resistivity falls dramatically as temperature rises, and it can be tuned over many orders of magnitude by controlled doping. Insulators (glass, rubber, quartz) sit above about 10^3 ohm.m, reaching as high as 10^17 ohm.m for the best synthetic insulators. Many practical materials - water, soil, biological tissue - fall in intermediate ranges and are classified situationally.
Temperature dependence and practical notes
The values in the reference table are for 20 C (68 F). In metals, resistivity increases roughly linearly with temperature because lattice vibrations scatter electrons more energetically at higher temperatures - this is a positive temperature coefficient (PTC). In semiconductors and insulators the opposite applies: more thermal energy frees additional charge carriers, so resistivity falls with rising temperature - a negative temperature coefficient (NTC). For precise work, use the linear approximation rho(T) = rho_0 x (1 + alpha x (T - T_0)), where alpha is the material-specific temperature coefficient of resistance. For copper, alpha is about 3.9 x 10^-3 per degree Celsius.
Electrical resistivity and conductivity at 20 C
| Material | Resistivity (ohm.m) | Conductivity (S/m) | Class |
|---|---|---|---|
| Silver | 1.59 x 10^-8 | 6.29 x 10^7 | Conductor |
| Copper | 1.68 x 10^-8 | 5.96 x 10^7 | Conductor |
| Gold | 2.44 x 10^-8 | 4.10 x 10^7 | Conductor |
| Aluminum | 2.82 x 10^-8 | 3.55 x 10^7 | Conductor |
| Calcium | 3.36 x 10^-8 | 2.98 x 10^7 | Conductor |
| Tungsten | 5.60 x 10^-8 | 1.79 x 10^7 | Conductor |
| Zinc | 5.90 x 10^-8 | 1.69 x 10^7 | Conductor |
| Nickel | 6.99 x 10^-8 | 1.43 x 10^7 | Conductor |
| Iron | 1.00 x 10^-7 | 1.00 x 10^7 | Conductor |
| Platinum | 1.06 x 10^-7 | 9.43 x 10^6 | Conductor |
| Tin | 1.09 x 10^-7 | 9.17 x 10^6 | Conductor |
| Lead | 2.20 x 10^-7 | 4.55 x 10^6 | Conductor |
| Titanium | 4.20 x 10^-7 | 2.38 x 10^6 | Conductor |
| Stainless steel | 6.90 x 10^-7 | 1.45 x 10^6 | Conductor |
| Nichrome | 1.10 x 10^-6 | 9.09 x 10^5 | Conductor |
| Germanium | 4.60 x 10^-4 | 2.17 x 10^3 | Semiconductor |
| Silicon | 6.40 x 10^2 | 1.56 x 10^-3 | Semiconductor |
| Glass | 1.00 x 10^12 | 1.00 x 10^-12 | Insulator |
| Rubber | 1.00 x 10^13 | 1.00 x 10^-13 | Insulator |
Standard values for common conductors, semiconductors, and insulators. All resistivity values are in ohm.m; all conductivity values are in S/m.
Frequently asked questions
What is the formula to convert conductivity to resistivity?
Resistivity (ohm.m) = 1 divided by conductivity (S/m). That is all there is to it: rho = 1 / sigma. The two quantities are exact reciprocals, so one completely determines the other. Make sure both values are expressed in SI units (S/m for conductivity, ohm.m for resistivity) before dividing; if your conductivity is in S/cm, multiply by 100 first to convert to S/m.
What is the difference between resistance and resistivity?
Resistance is the opposition to current flow measured in a specific object, and it depends on both the material and the geometry (length and cross-sectional area): R = rho x L / A, where L is length and A is cross-sectional area. Resistivity is the intrinsic material constant in that equation - it does not change when you make the object longer or thinner. Two copper wires of different sizes have the same resistivity but different resistances.
Which material has the highest electrical conductivity?
Silver has the highest conductivity of all elements at room temperature: about 6.30 x 10^7 S/m (resistivity 1.59 x 10^-8 ohm.m). Copper is a close second at about 5.96 x 10^7 S/m and is used far more widely because it is dramatically cheaper. Gold is third, and although less conductive than copper it is valued for its corrosion resistance in connectors.
Why is conductivity expressed in siemens per metre (S/m)?
The siemens (S) is the SI unit of electrical conductance, defined as the reciprocal of the ohm. One siemens = 1 ampere per volt (1 A/V). Conductivity is conductance per unit length and per unit cross-sectional area, which gives S/m as the unit. Because it is the reciprocal of ohm per metre, you will sometimes see the older notation (ohm.m)^-1 used in older texts - both mean exactly the same thing.
How does temperature affect resistivity?
For metals, resistivity increases with temperature because thermal energy increases lattice vibrations that scatter conduction electrons. The relationship is approximately linear near room temperature: rho(T) = rho_0 x (1 + alpha x delta T). For copper, alpha is about 3.9 x 10^-3 per degree Celsius. For semiconductors the opposite applies: more thermal energy creates more free charge carriers, so resistivity decreases with rising temperature. This is why thermistors used as NTC sensors are made from semiconductor materials.
Can conductivity and resistivity ever be zero or infinite?
In classical materials at room temperature, neither is exactly zero or infinite. However, superconductors below their critical temperature exhibit zero resistivity (infinite conductivity) - current flows without any energy loss. Conversely, a perfect vacuum has infinite resistivity (zero conductivity) because there are no charge carriers to transport current. Real insulators approach but do not reach infinite resistivity; even the best insulator has a finite, very high resistivity.