Femtosiemens is 1e-15 siemens units.
Femtosiemens to Siemens Converter — fS to S
Convert Femtosiemens (fS) to Siemens (S) using the exact conversion factor (1 femtosiemens = 1e-15 siemens). See the formula, worked examples, and conversion table.
Femtosiemens to Siemens converter
Converter
Electricity Converter
Convert electrical units by family and calculate voltage, current, resistance, power, and energy with context values.
Context values
Some unit families need one extra value for a physically accurate result.
Siemens is the SI unit of conductance.
Result = input x 1e-15 / 1.
Electrical units in the same family convert directly.
Reserved above the conversion cards and below the converter.
About Converting Femtosiemens to Siemens
Femtosiemens and Siemens both belong to the electricity family — voltage, current, resistance, power, or energy — units that show up constantly when working across the different standards used by household wiring (120V/240V depending on region), automotive electrical systems (12V/24V), and electronics design. Specifically: Femtosiemens is 1e-15 siemens units, and siemens is the SI unit of conductance.
Formula
siemens = femtosiemens × 1e-15
This factor comes from each unit's defined relationship to the category's base unit: 1 femtosiemens equals 1e-15 base units, and 1 siemens equals 1 base unit, so dividing one by the other gives the direct femtosiemens-to-siemens factor of 1e-15.
Simple example
1 fS × 1e-15 = 1e-15 S
1 femtosiemens = 1e-15 siemens.
Real-world example
120 fS × 1e-15 = 1.2e-13 S
120 femtosiemens = 1.2e-13 siemens.
Conversion table
| Femtosiemens (fS) | Siemens (S) |
|---|---|
| 1 fS | 1e-15 S |
| 5 fS | 5e-15 S |
| 12 fS | 1.2e-14 S |
| 24 fS | 2.4e-14 S |
| 120 fS | 1.2e-13 S |
| 240 fS | 2.4e-13 S |
Reverse conversion: Siemens to Femtosiemens
1e-15 S × 1e+15 = 1 fS
1e-15 siemens = 1 femtosiemens.
femtosiemens = siemens × 1e+15
For a page dedicated to this direction, see Siemens to Femtosiemens.
Understanding the Femtosiemens (fS)
Femtosiemens is 1e-15 siemens units.
Understanding the Siemens (S)
Siemens is the SI unit of conductance.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many siemens are in 1 femtosiemens?
1 femtosiemens equals 1e-15 siemens, using the exact defined conversion factor rather than an estimate.
How do I convert femtosiemens to siemens?
Multiply the femtosiemens value by 1e-15. The converter above does this instantly to whatever precision you set.
How do I convert siemens back to femtosiemens?
Use the reverse factor: 1 siemens equals 1e+15 femtosiemens. You can also use the swap control in the converter above to flip the direction instantly.
What is a femtosiemens?
Femtosiemens (fS) is a unit of electricity.
What is a siemens?
Siemens (S) is a unit of electricity.
Is the femtosiemens to siemens conversion exact?
Yes. Both femtosiemens and siemens are defined by fixed standards rather than physical artifacts, so the factor of 1e-15 used above is exact to as many digits as you choose to display.
What's the difference between voltage, current, and resistance?
Voltage (volts) is the electrical potential difference driving current through a circuit. Current (amperes) is the rate of flow of electric charge. Resistance (ohms) is how much a component opposes that flow. They're related by Ohm's law (V = I × R), but they are distinct physical quantities, and this page converts between units of just one of them.