What is being measured?
Power is the rate of energy transfer. Power and energy differ by a time interval; watts and watt-hours cannot be exchanged by a unit factor alone.
Horsepower is mechanical unless marked metric. PS equals metric horsepower. Refrigeration tons use the US 12,000 BTU IT/h convention.
Meaning of pW
Picowatts uses the symbol pW in this library and measures power. Under the stated reference convention, 1 pW = approximately 1e-12 W. This equivalence changes how a known value is written. It does not increase measurement accuracy or establish whether a measurement is appropriate to a real application.
Conversion method
Multiply the value by the source factor (1e-12), then divide by the target factor (1). The factor ratio expresses the same power measurement in the other unit.
Worked example
For a known value of 10 pW, the reference conversion gives 1e-11 W. Converting that result back gives approximately 10 pW. This reverse check helps catch a reversed factor, but matching round-trip arithmetic alone does not independently verify a source definition.
Common reference values
| Input (pW) | Reference equivalent (W) |
|---|---|
| 1 | 1e-12 |
| 5 | 5e-12 |
| 10 | 1e-11 |
| 25 | 2.5e-11 |
| 50 | 5e-11 |
| 100 | 1e-10 |
Compare one pW with other units
| Target unit | Equivalent of 1 pW | Definition guide |
|---|---|---|
| Watts (W) | 1e-12 | Read definition |
| Kilowatts (kW) | 1e-15 | Read definition |
| Megawatts (MW) | 1e-18 | Read definition |
| btu per hour (BTU IT/h) | 3.41214163313e-12 | Read definition |
| Mechanical horsepower (hp mech) | 1.3410220896e-15 | Read definition |
| metric horsepower (hp metric) | 1.3596216173e-15 | Read definition |
| tons of refrigeration (TR) | 2.84345136094e-16 | Read definition |
| Nanowatts (nW) | 0.001 | Read definition |
Precision and common mistakes
- Keep the source and target quantity consistent. A matching symbol is not enough to establish a compatible definition.
- Record the original measurement precision. Showing twelve significant digits in a table does not make a rounded input more precise.
- Check symbol capitalization, prefixes and any regional convention in the source. Use the displayed unit definition rather than a similarly named unit.
- Factors involving repeating fractions or π use finite numerical precision. Round the final answer to the precision justified by your input.
Use a working converter
- Power converter
- Picowatts to Watts converter
- Picowatts to Kilowatts converter
- Picowatts to Megawatts converter
- Picowatts to btu per hour converter
- Picowatts to Mechanical horsepower converter
Source and verification scope
Examples and tables are computed from the versioned unit definitions used by the linked converters. The source access dates appear below. Computandum is independent of the cited organizations; a citation does not mean that a publisher endorses this page or an actual project.
Sources
- NIST / BIPM: NIST: unit conversion factors ↗ · 2026-10-08