About this converter
Electric conductance is the reciprocal of electrical resistance, measuring how easily current flows through a conductor or solution. The SI unit is the siemens (S), defined as 1 ampere per volt (A/V). Named after German engineer Ernst von Siemens, it was previously called the mho — ohm spelled backward.
Electrical engineers, lab chemists, and semiconductor technicians routinely convert between siemens prefixes and CGS units. Water quality analysts measure solution conductivity in µS/cm, circuit designers characterize transistor transconductance in millisiemens, and precision metrologists use quantized Hall conductance (≈ 3.874 × 10⁻⁵ S) as a quantum reference standard.
How to Use This Converter
- Enter the conductance value in the Value field.
- Select the source unit in the From dropdown.
- Select the target unit in the To dropdown.
- Read the converted result and the formula line below.
- Use Swap to reverse the direction in one click.
Units Covered
| Unit | Symbol | Common Use |
|---|---|---|
| Siemens | S | SI base unit for conductance; used across all electrical disciplines. |
| Megasiemens | MS | High-conductance materials and bus bar specifications. |
| Kilosiemens | kS | Large conductor and electrolyte tank measurements. |
| Millisiemens | mS | Transistor small-signal parameters and ionic solutions. |
| Microsiemens | µS | Water quality measurement; drinking water is typically 200–400 µS/cm. |
| Ampere/volt | A/V | Equivalent to siemens; used in some power electronics texts. |
| Mho | mho | Legacy term identical to siemens; still used in some US textbooks. |
| Gemmho | Gemmho | Older CGS microsiemens equivalent; found in vintage circuit literature. |
| Micromho | Micromho | CGS equivalent of microsiemens; used in older US engineering references. |
| Abmho | Abmho | CGS electromagnetic unit; 1 abmho = 10⁹ S. |
| Statmho | Statmho | CGS electrostatic unit; 1 statmho ≈ 1.112 × 10⁻¹² S. |
| Quantized Hall conductance | e²/h | Quantum standard used in precision metrology and resistance calibration. |
How to Convert Siemens to Millisiemens
Siemens to millisiemens
For example, 0.025 S × 1000 = 25 mS.
Millisiemens to siemens
For example, 250 mS / 1000 = 0.25 S.
When You Need to Convert Conductance
Water quality analysts use microsiemens to characterize water purity. Drinking water typically measures 200–400 µS/cm, seawater around 50,000 µS/cm, and deionized lab water below 0.1 µS/cm. Converting these readings to siemens or millisiemens is routine when comparing measurement standards across different instruments.
Semiconductor engineers characterize bipolar transistor forward transconductance (gm) in millisiemens. A BJT biased at 1 mA has gm = 38.5 mS at room temperature, which simplifies small-signal amplifier gain calculations. Converting gm between S and mS avoids order-of-magnitude errors in SPICE simulations.
Quantum metrologists use quantized Hall conductance (e²/h ≈ 3.874 × 10⁻⁵ S) as an SI-traceable reference. National measurement institutes calibrate resistance standards against this quantum unit, making the siemens ↔ QHC conversion essential in precision electrical calibration laboratories.