Conductance Calculator

Enter a resistance in ohms to get the conductance.

Result

0.004545 S
4.55 mS

How it is calculated

The tool takes one number, the resistance R in ohms (Ω), and returns G = 1 / R in siemens (S). The result is shown rounded to six decimal places in siemens and, separately, as G × 1000 in millisiemens (mS) rounded to two decimals. Resistance must be strictly greater than zero: an empty field, zero or a negative value gives no result, because 1/0 is undefined and this tool does not model negative resistance. Because small conductances are tiny numbers, a very large resistance (several megaohms) will round towards 0.000000 S in the siemens line; use the resistance directly in that case.

Worked example

Take a 220 Ω resistor. Divide 1 by 220: 1 / 220 = 0.0045454…. Rounded to six decimals that is 0.004545 S. Multiplying the unrounded value by 1000 gives 4.5454… mS, shown as 4.55 mS. As a check, 1 / 0.004545 S is about 220 Ω, and a 440 Ω resistor would have exactly half this conductance.

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Common mistakes

  • Entering the resistance in kilohms or megohms while the field expects plain ohms. A 4.7 kΩ resistor must be typed as 4700, otherwise the answer is 1000 times too large.
  • Typing 0 for a short circuit or a wire. The conductance would be infinite, so the tool returns nothing instead of a number.
  • Adding conductances of parallel parts after converting each one by hand and then forgetting to convert the sum back: parallel conductances add directly, but the equivalent resistance is the reciprocal of that sum.
  • Reading the millisiemens line as the siemens value. 4.55 mS is 0.00455 S, not 4.55 S.

About this calculator

Electrical conductance (G) is the reciprocal of resistance, G = 1/R, expressed in siemens (S) — a unit named after German engineer Werner von Siemens and defined as amperes per volt. Where resistance tells you how strongly a component opposes current, conductance tells you how easily current flows through it, which is the more natural quantity when components are combined in parallel: parallel conductances simply add (G_total = G1 + G2 + ...), unlike parallel resistances.

Electrical and electronics engineers reach for conductance when analyzing parallel networks, admittance in AC circuits (where conductance is the real part of admittance, Y = G + jB), and in semiconductor datasheets that specify transconductance-related parameters for transistors and MOSFETs.

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