Femtowatt is 1e-15 watt units.
Femtowatts to Ronnawatts Converter — fW to RW
Convert Femtowatt (fW) to Ronnawatt (RW) using the exact conversion factor (1 femtowatt = 1e-42 ronnawatt). See the formula, worked examples, and conversion table.
Femtowatts to Ronnawatts 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.
Ronnawatt is 1e+27 watt units.
Result = input x 1e-15 / 1e+27.
Electrical units in the same family convert directly.
Reserved above the conversion cards and below the converter.
About Converting Femtowatts to Ronnawatts
Femtowatt and Ronnawatt 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: Femtowatt is 1e-15 watt units, and ronnawatt is 1e+27 watt units.
Formula
ronnawatts = femtowatts × 1e-42
This factor comes from each unit's defined relationship to the category's base unit: 1 femtowatt equals 1e-15 base units, and 1 ronnawatt equals 1e+27 base units, so dividing one by the other gives the direct femtowatt-to-ronnawatt factor of 1e-42.
Simple example
1 fW × 1e-42 = 1e-42 RW
1 femtowatt = 1e-42 ronnawatts.
Real-world example
120 fW × 1e-42 = 1.2e-40 RW
120 femtowatts = 1.2e-40 ronnawatts.
Conversion table
| Femtowatt (fW) | Ronnawatt (RW) |
|---|---|
| 1 fW | 1e-42 RW |
| 5 fW | 5e-42 RW |
| 12 fW | 1.2e-41 RW |
| 24 fW | 2.4e-41 RW |
| 120 fW | 1.2e-40 RW |
| 240 fW | 2.4e-40 RW |
Reverse conversion: Ronnawatt to Femtowatt
1e-42 RW × 1e+42 = 1 fW
1e-42 ronnawatts = 1 femtowatt.
femtowatts = ronnawatts × 1e+42
For a page dedicated to this direction, see Ronnawatt to Femtowatt.
Understanding the Femtowatt (fW)
Femtowatt is 1e-15 watt units.
Understanding the Ronnawatt (RW)
Ronnawatt is 1e+27 watt units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many ronnawatts are in 1 femtowatt?
1 femtowatt equals 1e-42 ronnawatts, using the exact defined conversion factor rather than an estimate.
How do I convert femtowatt to ronnawatt?
Multiply the femtowatt value by 1e-42. The converter above does this instantly to whatever precision you set.
How do I convert ronnawatt back to femtowatt?
Use the reverse factor: 1 ronnawatt equals 1e+42 femtowatts. You can also use the swap control in the converter above to flip the direction instantly.
What is a femtowatt?
Femtowatt (fW) is a unit of electricity.
What is a ronnawatt?
Ronnawatt (RW) is a unit of electricity.
Is the femtowatt to ronnawatt conversion exact?
Yes. Both femtowatt and ronnawatt are defined by fixed standards rather than physical artifacts, so the factor of 1e-42 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.