Conductivity to Resistivity Calculator
This calculator converts electrical conductivity into electrical resistivity, and back again, using the exact reciprocal relationship rho = 1 / sigma. Conductivity (sigma) describes how easily a material lets electric current flow, while resistivity (rho) describes how strongly it resists that flow, so the two values sit on opposite ends of the same scale. Enter your own conductivity figure in siemens per metre (S/m) or siemens per centimetre (S/cm), or pick a preset for a common material such as copper, aluminium, iron, stainless steel, nichrome, doped or intrinsic silicon, glass, rubber or PTFE, then choose whether you want results in SI units (S/m and ohm-metres) or CGS units (S/cm and ohm-centimetres). You get back the resistivity and formula used, plus a breakdown into nano-, micro- and milliohm-scale units for both systems. A reference table lists conductivity and resistivity for common conductors, semiconductors and insulators, and a summary line classifies your result against that scale. Use it to choose cable materials, check semiconductor doping levels, interpret water or soil conductivity readings, or convert between textbooks and datasheets using different unit conventions. Because the maths is an exact reciprocal, the conversion itself is always precise, but the preset values are typical figures at around 20 degrees Celsius; real resistivity for semiconductors can shift with temperature, doping and purity, so check a datasheet before relying on it for precision engineering work.
1. Material Preset
2. Custom Input
SI Unit Result
CGS Unit Result
Common Materials Reference Table
| Material | Conductivity (S/m) | Resistivity (Ω·m) | Category |
|---|---|---|---|
| Copper | 5.96 × 107 | 1.68 × 10-8 | Conductor |
| Aluminium | 3.77 × 107 | 2.65 × 10-8 | Conductor |
| Iron | 1.00 × 107 | 1.00 × 10-7 | Conductor |
| Stainless steel | 4.55 × 106 | 2.20 × 10-7 | Conductor |
| Nichrome | 1.56 × 106 | 6.41 × 10-7 | Resistive alloy |
| Silicon (doped) | 1,000 | 1.00 × 10-3 | Semiconductor |
| Silicon (intrinsic) | 4.4 × 10-4 | 2.27 × 103 | Semiconductor |
| Glass | 10-10 to 10-14 | 1010 to 1014 | Insulator |
| PTFE (Teflon) | ~10-15 | ~1015 | Insulator |
How Conductivity and Resistivity Are Related
Electrical conductivity (symbol: sigma, unit: siemens per metre, S/m) and electrical resistivity (symbol: rho, unit: ohm-metres, Ω·m) are reciprocal properties of a material. The relationship is exact:
rho = 1 / sigma and sigma = 1 / rho
Conductivity describes how easily electrical current flows through a material. A material with high conductivity (like copper at about 5.96 × 107 S/m) allows current to flow with very little opposition. Resistivity describes the same property from the opposite perspective: how strongly the material resists current flow. High resistivity means the material is a good insulator.
Units and Unit Conversion
The SI unit system uses S/m for conductivity and Ω·m for resistivity. Some fields, particularly semiconductor engineering and electrochemistry, use the CGS unit system with S/cm and Ω·cm. The conversion between SI and CGS is:
- 1 S/m = 0.01 S/cm
- 1 Ω·m = 100 Ω·cm
So if you have a conductivity of 5.96 × 107 S/m, this equals 5.96 × 105 S/cm, and the corresponding resistivity of 1.678 × 10-8 Ω·m equals 1.678 × 10-6 Ω·cm (or 1.678 μΩ·cm).
Worked Example
Given: Copper has a conductivity of 5.96 × 107 S/m.
Find: Resistivity of copper.
Formula: rho = 1 / sigma
Calculation: rho = 1 / (5.96 × 107) = 1.678 × 10-8 Ω·m = 16.78 nΩ·m
This matches the accepted value for the resistivity of copper at room temperature (approximately 20 °C): 1.678 × 10-8 Ω·m or 1.678 μΩ·cm.
Conductors, Semiconductors, and Insulators
Materials are classified by their resistivity:
- Conductors (metals): resistivity typically below 10-6 Ω·m. Examples: copper, aluminium, gold, iron.
- Semiconductors: resistivity typically between 10-4 and 104 Ω·m. Examples: silicon, germanium. Resistivity varies greatly with doping, temperature, and light exposure.
- Insulators: resistivity typically above 108 Ω·m. Examples: glass, rubber, PTFE (Teflon), quartz.
Applications
Conductivity and resistivity values are used in many engineering contexts:
- Selecting cable and wire materials for electrical installations based on resistivity and cost.
- Semiconductor device design, where doping levels control resistivity precisely.
- Water quality testing: water conductivity is measured in S/m or mS/cm and indicates dissolved mineral content.
- Soil and geotechnical surveys, where soil resistivity affects grounding electrode performance and corrosion risk.
- Electromagnetic shielding, where the conductivity of a shield material determines its effectiveness.
Related Calculators
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Sources and method: Reciprocal relationship rho = 1 / sigma is a standard definition in electromagnetism. Material values sourced from standard engineering references (CRC Handbook of Chemistry and Physics; Serway & Jewett, Physics for Scientists and Engineers). All calculations are exact mathematical conversions using the reciprocal formula.
Note: Resistivity and conductivity values for semiconductors vary significantly with temperature, doping concentration, and crystal structure. The values shown in the material presets are typical values at approximately 20 °C. Always verify against material datasheets for precision engineering applications.