Zeptowatt is 1e-21 watt units.
Zeptowatts to Attowatts Converter — zW to aW
Convert Zeptowatt (zW) to Attowatt (aW) using the exact conversion factor (1 zeptowatt = 0.001 attowatt). See the formula, worked examples, and conversion table.
Zeptowatts to Attowatts 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.
Attowatt is 1e-18 watt units.
Result = input x 1e-21 / 1e-18.
Power uses the watt as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Zeptowatts to Attowatts
Zeptowatt and Attowatt 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: Zeptowatt is 1e-21 watt units, and attowatt is 1e-18 watt units.
Formula
attowatts = zeptowatts × 0.001
This factor comes from each unit's defined relationship to the category's base unit: 1 zeptowatt equals 1e-21 base units, and 1 attowatt equals 1e-18 base units, so dividing one by the other gives the direct zeptowatt-to-attowatt factor of 0.001.
Simple example
1 zW × 0.001 = 0.001 aW
1 zeptowatt = 0.001 attowatts.
Real-world example
100 zW × 0.001 = 0.1 aW
100 zeptowatts = 0.1 attowatts.
Conversion table
| Zeptowatt (zW) | Attowatt (aW) |
|---|---|
| 1 zW | 0.001 aW |
| 10 zW | 0.01 aW |
| 100 zW | 0.1 aW |
| 500 zW | 0.5 aW |
| 1,000 zW | 1 aW |
| 5,000 zW | 5 aW |
Reverse conversion: Attowatt to Zeptowatt
0.001 aW × 1000 = 1 zW
0.001 attowatts = 1 zeptowatts.
zeptowatts = attowatts × 1000
For a page dedicated to this direction, see Attowatt to Zeptowatt.
Understanding the Zeptowatt (zW)
Zeptowatt is 1e-21 watt units.
Understanding the Attowatt (aW)
Attowatt is 1e-18 watt units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many attowatts are in 1 zeptowatt?
1 zeptowatt equals 0.001 attowatts, using the exact defined conversion factor rather than an estimate.
How do I convert zeptowatt to attowatt?
Multiply the zeptowatt value by 0.001. The converter above does this instantly to whatever precision you set.
How do I convert attowatt back to zeptowatt?
Use the reverse factor: 1 attowatt equals 1,000 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 power.
What is a attowatt?
Attowatt (aW) is a unit of power.
Is the zeptowatt to attowatt conversion exact?
Yes. Both zeptowatt and attowatt are defined by fixed standards rather than physical artifacts, so the factor of 0.001 used above is exact to as many digits as you choose to display.