Zeptowatt is 1e-21 watt units.
Zeptowatts to Femtowatts Converter — zW to fW
Convert Zeptowatt (zW) to Femtowatt (fW) using the exact conversion factor (1 zeptowatt = 1e-6 femtowatt). See the formula, worked examples, and conversion table.
Zeptowatts to Femtowatts 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.
Femtowatt is 1e-15 watt units.
Result = input x 1e-21 / 1e-15.
Power units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Zeptowatts to Femtowatts
Zeptowatt and Femtowatt 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: Zeptowatt is 1e-21 watt units, and femtowatt is 1e-15 watt units.
Formula
femtowatts = zeptowatts × 1e-6
This factor comes from each unit's defined relationship to the category's base unit: 1 zeptowatt equals 1e-21 base units, and 1 femtowatt equals 1e-15 base units, so dividing one by the other gives the direct zeptowatt-to-femtowatt factor of 1e-6.
Simple example
1 zW × 1e-6 = 1e-6 fW
1 zeptowatt = 1e-6 femtowatts.
Real-world example
100 zW × 1e-6 = 0.0001 fW
100 zeptowatts = 0.0001 femtowatts.
Conversion table
| Zeptowatt (zW) | Femtowatt (fW) |
|---|---|
| 1 zW | 1e-6 fW |
| 10 zW | 0.00001 fW |
| 50 zW | 0.00005 fW |
| 100 zW | 0.0001 fW |
| 500 zW | 0.0005 fW |
| 1,000 zW | 0.001 fW |
Reverse conversion: Femtowatt to Zeptowatt
0.000001 fW × 1000000 = 1 zW
0.000001 femtowatts = 1 zeptowatts.
zeptowatts = femtowatts × 1000000
For a page dedicated to this direction, see Femtowatt to Zeptowatt.
Understanding the Zeptowatt (zW)
Zeptowatt is 1e-21 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 zeptowatt?
1 zeptowatt equals 1e-6 femtowatts, using the exact defined conversion factor rather than an estimate.
How do I convert zeptowatt to femtowatt?
Multiply the zeptowatt value by 1e-6. The converter above does this instantly to whatever precision you set.
How do I convert femtowatt back to zeptowatt?
Use the reverse factor: 1 femtowatt equals 1,000,000 zeptowatts. You can also use the swap control in the converter above to flip the direction instantly.
What is a zeptowatt?
Zeptowatt (zW) is a unit of engineering.
What is a femtowatt?
Femtowatt (fW) is a unit of engineering.
Is the zeptowatt to femtowatt conversion exact?
Yes. Both zeptowatt and femtowatt are defined by fixed standards rather than physical artifacts, so the factor of 1e-6 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.