Femtowatt is 1e-15 watt units.
Femtowatts to Zeptowatts Converter — fW to zW
Convert Femtowatt (fW) to Zeptowatt (zW) using the exact conversion factor (1 femtowatt = 1,000,000 zeptowatt). See the formula, worked examples, and conversion table.
Femtowatts to Zeptowatts converter
Converter
Engineering Converter
Convert common stress, force, torque, power, and energy units used in engineering.
Context values
Some unit families need one extra value for a physically accurate result.
Zeptowatt is 1e-21 watt units.
Result = input x 1e-15 / 1e-21.
Power units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Femtowatts to Zeptowatts
Femtowatt and Zeptowatt both measure a quantity used in structural or mechanical engineering — commonly stress, pressure, force, torque, power, or energy — where converting between the unit conventions used in different regions, industries, or equipment specifications is a routine part of design work. Specifically: Femtowatt is 1e-15 watt units, and zeptowatt is 1e-21 watt units.
Formula
zeptowatts = femtowatts × 1000000
This factor comes from each unit's defined relationship to the category's base unit: 1 femtowatt equals 1e-15 base units, and 1 zeptowatt equals 1e-21 base units, so dividing one by the other gives the direct femtowatt-to-zeptowatt factor of 1000000.
Simple example
1 fW × 1000000 = 1,000,000 zW
1 femtowatt = 1,000,000 zeptowatts.
Real-world example
100 fW × 1000000 = 100,000,000 zW
100 femtowatts = 100,000,000 zeptowatts.
Conversion table
| Femtowatt (fW) | Zeptowatt (zW) |
|---|---|
| 1 fW | 1,000,000 zW |
| 10 fW | 10,000,000 zW |
| 50 fW | 50,000,000 zW |
| 100 fW | 100,000,000 zW |
| 500 fW | 500,000,000 zW |
| 1,000 fW | 1,000,000,000 zW |
Reverse conversion: Zeptowatt to Femtowatt
1 zW × 1e-6 = 1e-6 fW
1 zeptowatt = 1e-6 femtowatts.
femtowatts = zeptowatts × 1e-6
For a page dedicated to this direction, see Zeptowatt to Femtowatt.
Understanding the Femtowatt (fW)
Femtowatt is 1e-15 watt units.
Understanding the Zeptowatt (zW)
Zeptowatt is 1e-21 watt units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many zeptowatts are in 1 femtowatt?
1 femtowatt equals 1,000,000 zeptowatts, using the exact defined conversion factor rather than an estimate.
How do I convert femtowatt to zeptowatt?
Multiply the femtowatt value by 1000000. The converter above does this instantly to whatever precision you set.
How do I convert zeptowatt back to femtowatt?
Use the reverse factor: 1 zeptowatt equals 1e-6 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 engineering.
What is a zeptowatt?
Zeptowatt (zW) is a unit of engineering.
Is the femtowatt to zeptowatt conversion exact?
Yes. Both femtowatt and zeptowatt are defined by fixed standards rather than physical artifacts, so the factor of 1000000 used above is exact to as many digits as you choose to display.
Why do engineering unit conventions vary so much by region and industry?
Pressure, force, and stress can be expressed in metric (pascal, newton), US customary (psi, pound-force), or older and industry-specific units (atmosphere, torr, kip) depending on the country, industry, and even the equipment manufacturer, which is why engineers routinely need to convert between them when working across specs from different sources.