Milliwatt is 0.001 watt units.
Milliwatts to Zeptowatts Converter — mW to zW
Convert Milliwatt (mW) to Zeptowatt (zW) using the exact conversion factor (1 milliwatt = 1e+18 zeptowatt). See the formula, worked examples, and conversion table.
Milliwatts to Zeptowatts 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.
Zeptowatt is 1e-21 watt units.
Result = input x 0.001 / 1e-21.
Power uses the watt as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Milliwatts to Zeptowatts
Milliwatt and Zeptowatt 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: Milliwatt is 0.001 watt units, and zeptowatt is 1e-21 watt units.
Formula
zeptowatts = milliwatts × 1e+18
This factor comes from each unit's defined relationship to the category's base unit: 1 milliwatt equals 0.001 base units, and 1 zeptowatt equals 1e-21 base units, so dividing one by the other gives the direct milliwatt-to-zeptowatt factor of 1e+18.
Simple example
1 mW × 1e+18 = 1e+18 zW
1 milliwatt = 1e+18 zeptowatts.
Real-world example
100 mW × 1e+18 = 1e+20 zW
100 milliwatts = 1e+20 zeptowatts.
Conversion table
| Milliwatt (mW) | Zeptowatt (zW) |
|---|---|
| 1 mW | 1e+18 zW |
| 10 mW | 1e+19 zW |
| 100 mW | 1e+20 zW |
| 500 mW | 5e+20 zW |
| 1,000 mW | 1e+21 zW |
| 5,000 mW | 5e+21 zW |
Reverse conversion: Zeptowatt to Milliwatt
1e+18 zW × 1e-18 = 1 mW
1e+18 zeptowatts = 1 milliwatts.
milliwatts = zeptowatts × 1e-18
For a page dedicated to this direction, see Zeptowatt to Milliwatt.
Understanding the Milliwatt (mW)
Milliwatt is 0.001 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 milliwatt?
1 milliwatt equals 1e+18 zeptowatts, using the exact defined conversion factor rather than an estimate.
How do I convert milliwatt to zeptowatt?
Multiply the milliwatt value by 1e+18. The converter above does this instantly to whatever precision you set.
How do I convert zeptowatt back to milliwatt?
Use the reverse factor: 1 zeptowatt equals 1e-18 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 power.
What is a zeptowatt?
Zeptowatt (zW) is a unit of power.
Is the milliwatt to zeptowatt conversion exact?
Yes. Both milliwatt and zeptowatt 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.