Femtowatt is 1e-15 watt units.
Femtowatts to Kilowatts Converter — fW to kW
Convert Femtowatt (fW) to Kilowatt (kW) using the exact conversion factor (1 femtowatt = 1e-18 kilowatt). See the formula, worked examples, conversion table, history, and common uses.
Femtowatts to Kilowatts converter
Converter
Power Converter
Convert watts, horsepower, refrigeration tons, BTU per hour, and engineering power units.
Context values
Some unit families need one extra value for a physically accurate result.
Kilowatt is 1000 watt units.
Result = input x 1e-15 / 1000.
Power uses the watt as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Femtowatts to Kilowatts
Femtowatt and Kilowatt both describe power output, and the conversion is a routine part of comparing an engine or motor's spec sheet across countries that use different power units. Specifically: Femtowatt is 1e-15 watt units, and kilowatt is 1000 watt units.
Formula
kilowatts = femtowatts × 1e-18
This factor comes from each unit's defined relationship to the category's base unit: 1 femtowatt equals 1e-15 base units, and 1 kilowatt equals 1000 base units, so dividing one by the other gives the direct femtowatt-to-kilowatt factor of 1e-18.
Simple example
1 fW × 1e-18 = 1e-18 kW
1 femtowatt = 1e-18 kilowatts.
Real-world example
100 fW × 1e-18 = 1e-16 kW
100 femtowatts = 1e-16 kilowatts.
Conversion table
| Femtowatt (fW) | Kilowatt (kW) |
|---|---|
| 1 fW | 1e-18 kW |
| 10 fW | 1e-17 kW |
| 100 fW | 1e-16 kW |
| 500 fW | 5e-16 kW |
| 1,000 fW | 1e-15 kW |
| 5,000 fW | 5e-15 kW |
Reverse conversion: Kilowatt to Femtowatt
1e-18 kW × 1e+18 = 1 fW
1e-18 kilowatts = 1 femtowatt.
femtowatts = kilowatts × 1e+18
For a page dedicated to this direction, see Kilowatt to Femtowatt.
Understanding the Femtowatt (fW)
Femtowatt is 1e-15 watt units.
Understanding the Kilowatt
Kilowatt (kW) measures power. A kilowatt is 1,000 watts. It is classified as a SI derived (metric prefix) unit.
Where it's used: Standard power unit worldwide for larger appliances, vehicles, and electrical systems
Uses of the Kilowatt today
- Electric vehicle motor power ratings (alongside horsepower)
- Household electrical system and generator capacity
- Industrial motor and equipment power ratings
History of the Kilowatt
The kilowatt follows directly from the watt via the standard SI 'kilo-' prefix, becoming especially prominent with the growth of electrical power generation and distribution in the late 19th and 20th centuries.
Historical origin. Kilowatt was not the invention of a single named person; it developed through the process described above.
Kilowatt — sources
- BIPM SI Brochure — SI prefixes — Defines 'kilo-' as the prefix for 10³.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many kilowatts are in 1 femtowatt?
1 femtowatt equals 1e-18 kilowatts, using the exact defined conversion factor rather than an estimate.
How do I convert femtowatt to kilowatt?
Multiply the femtowatt value by 1e-18. The converter above does this instantly to whatever precision you set.
How do I convert kilowatt back to femtowatt?
Use the reverse factor: 1 kilowatt equals 1e+18 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 power.
What is a kilowatt?
Kilowatt (kW) measures power. A kilowatt is 1,000 watts. It is classified as a SI derived (metric prefix) unit.
Is the femtowatt to kilowatt conversion exact?
Yes. Both femtowatt and kilowatt are defined by fixed standards rather than physical artifacts, so the factor of 1e-18 used above is exact to as many digits as you choose to display.