Milliwatt is 0.001 watt units.
Milliwatts to Femtowatts Converter — mW to fW
Convert Milliwatt (mW) to Femtowatt (fW) using the exact conversion factor (1 milliwatt = 1e+12 femtowatt). See the formula, worked examples, and conversion table.
Milliwatts to Femtowatts 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.
Femtowatt is 1e-15 watt units.
Result = input x 0.001 / 1e-15.
Electrical units in the same family convert directly.
Reserved above the conversion cards and below the converter.
About Converting Milliwatts to Femtowatts
Milliwatt and Femtowatt 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: Milliwatt is 0.001 watt units, and femtowatt is 1e-15 watt units.
Formula
femtowatts = milliwatts × 1e+12
This factor comes from each unit's defined relationship to the category's base unit: 1 milliwatt equals 0.001 base units, and 1 femtowatt equals 1e-15 base units, so dividing one by the other gives the direct milliwatt-to-femtowatt factor of 1e+12.
Simple example
1 mW × 1e+12 = 1e+12 fW
1 milliwatt = 1e+12 femtowatts.
Real-world example
120 mW × 1e+12 = 1.2e+14 fW
120 milliwatts = 1.2e+14 femtowatts.
Conversion table
| Milliwatt (mW) | Femtowatt (fW) |
|---|---|
| 1 mW | 1e+12 fW |
| 5 mW | 5e+12 fW |
| 12 mW | 1.2e+13 fW |
| 24 mW | 2.4e+13 fW |
| 120 mW | 1.2e+14 fW |
| 240 mW | 2.4e+14 fW |
Reverse conversion: Femtowatt to Milliwatt
1e+12 fW × 1e-12 = 1 mW
1e+12 femtowatts = 1 milliwatt.
milliwatts = femtowatts × 1e-12
For a page dedicated to this direction, see Femtowatt to Milliwatt.
Understanding the Milliwatt (mW)
Milliwatt is 0.001 watt units.
Understanding the Femtowatt (fW)
Femtowatt is 1e-15 watt units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many femtowatts are in 1 milliwatt?
1 milliwatt equals 1e+12 femtowatts, using the exact defined conversion factor rather than an estimate.
How do I convert milliwatt to femtowatt?
Multiply the milliwatt value by 1e+12. The converter above does this instantly to whatever precision you set.
How do I convert femtowatt back to milliwatt?
Use the reverse factor: 1 femtowatt equals 1e-12 milliwatts. You can also use the swap control in the converter above to flip the direction instantly.
What is a milliwatt?
Milliwatt (mW) is a unit of electricity.
What is a femtowatt?
Femtowatt (fW) is a unit of electricity.
Is the milliwatt to femtowatt conversion exact?
Yes. Both milliwatt and femtowatt are defined by fixed standards rather than physical artifacts, so the factor of 1e+12 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.