Watt is one joule per second.
Watts to Zettawatts Converter — W to ZW
Convert Watt (W) to Zettawatt (ZW) using the exact conversion factor (1 watt = 1e-21 zettawatt). See the formula, worked examples, conversion table, history, and common uses.
Watts to Zettawatts converter
Converter
Electricity Converter
Convert electrical units by family and calculate voltage, current, resistance, power, and energy with context values.
Context values
Some unit families need one extra value for a physically accurate result.
Zettawatt is 1e+21 watt units.
Result = input x 1 / 1e+21.
Electrical units in the same family convert directly.
Reserved above the conversion cards and below the converter.
About Converting Watts to Zettawatts
Watt and Zettawatt both belong to the electricity family — voltage, current, resistance, power, or energy — units that show up constantly when working across the different standards used by household wiring (120V/240V depending on region), automotive electrical systems (12V/24V), and electronics design. Watt is most often used for electrical appliance power ratings worldwide.
Formula
zettawatts = watts × 1e-21
This factor comes from each unit's defined relationship to the category's base unit: 1 watt equals 1 base unit, and 1 zettawatt equals 1e+21 base units, so dividing one by the other gives the direct watt-to-zettawatt factor of 1e-21.
Simple example
1 W × 1e-21 = 1e-21 ZW
1 watt = 1e-21 zettawatts.
Real-world example
120 W × 1e-21 = 1.2e-19 ZW
120 watts = 1.2e-19 zettawatts.
Conversion table
| Watt (W) | Zettawatt (ZW) |
|---|---|
| 1 W | 1e-21 ZW |
| 5 W | 5e-21 ZW |
| 12 W | 1.2e-20 ZW |
| 24 W | 2.4e-20 ZW |
| 120 W | 1.2e-19 ZW |
| 240 W | 2.4e-19 ZW |
Reverse conversion: Zettawatt to Watt
1e-21 ZW × 1e+21 = 1 W
1e-21 zettawatts = 1 watts.
watts = zettawatts × 1e+21
For a page dedicated to this direction, see Zettawatt to Watt.
Understanding the Watt
Watt (W) measures power. The watt is the SI derived unit of power: one joule of energy per second. It is classified as a SI derived unit.
Where it's used: Standard scientific and everyday power unit worldwide
Uses of the Watt today
- Electrical appliance power ratings worldwide
- Light bulb brightness-equivalent labeling
- Engine and motor power specifications (alongside horsepower)
History of the Watt
The watt is named after James Watt, whose improvements to the steam engine in the late 18th century were commercially pivotal; ironically, Watt himself used horsepower (a unit he helped popularize) to market his engines. The watt was formally adopted as a unit at the 1889 General Conference on Weights and Measures and became the SI derived unit of power in the 20th century.
Historical origin. Watt was not the invention of a single named person; it developed through the process described above.
Understanding the Zettawatt (ZW)
Zettawatt is 1e+21 watt units.
Watt — sources
- BIPM SI Brochure — Coherent derived units — Defines the watt as the SI unit of power.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many zettawatts are in 1 watt?
1 watt equals 1e-21 zettawatts, using the exact defined conversion factor rather than an estimate.
How do I convert watt to zettawatt?
Multiply the watt value by 1e-21. The converter above does this instantly to whatever precision you set.
How do I convert zettawatt back to watt?
Use the reverse factor: 1 zettawatt equals 1e+21 watts. You can also use the swap control in the converter above to flip the direction instantly.
What is a watt?
Watt (W) measures power. The watt is the SI derived unit of power: one joule of energy per second. It is classified as a SI derived unit.
What is a zettawatt?
Zettawatt (ZW) is a unit of electricity.
Is the watt to zettawatt conversion exact?
Yes. Both watt and zettawatt are defined by fixed standards rather than physical artifacts, so the factor of 1e-21 used above is exact to as many digits as you choose to display.
Where is the watt still used today?
Standard scientific and everyday power unit worldwide
What's the difference between voltage, current, and resistance?
Voltage (volts) is the electrical potential difference driving current through a circuit. Current (amperes) is the rate of flow of electric charge. Resistance (ohms) is how much a component opposes that flow. They're related by Ohm's law (V = I × R), but they are distinct physical quantities, and this page converts between units of just one of them.