Attopascal is 1e-18 pascal units.
Attopascals to Hectopascals Converter — aPa to hPa
Convert Attopascal (aPa) to Hectopascal (hPa) using the exact conversion factor (1 attopascal = 1e-20 hectopascal). See the formula, worked examples, and conversion table.
Attopascals to Hectopascals converter
Converter
Pressure Converter
Convert pascals, bars, PSI, atmospheres, mercury columns, water columns, and engineering pressure units.
Context values
Some unit families need one extra value for a physically accurate result.
Hectopascal is 100 pascal units.
Result = input x 1e-18 / 100.
Pressure uses the pascal as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Attopascals to Hectopascals
Attopascal and Hectopascal both show up on pressure gauges — psi is standard on US tire and tool specifications, while bar is the everyday pressure unit across most of the rest of the world. Specifically: Attopascal is 1e-18 pascal units, and hectopascal is 100 pascal units.
Formula
hectopascals = attopascals × 1e-20
This factor comes from each unit's defined relationship to the category's base unit: 1 attopascal equals 1e-18 base units, and 1 hectopascal equals 100 base units, so dividing one by the other gives the direct attopascal-to-hectopascal factor of 1e-20.
Simple example
1 aPa × 1e-20 = 1e-20 hPa
1 attopascal = 1e-20 hectopascals.
Real-world example
35 aPa × 1e-20 = 3.5e-19 hPa
35 attopascals = 3.5e-19 hectopascals.
Conversion table
| Attopascal (aPa) | Hectopascal (hPa) |
|---|---|
| 1 aPa | 1e-20 hPa |
| 5 aPa | 5e-20 hPa |
| 10 aPa | 1e-19 hPa |
| 25 aPa | 2.5e-19 hPa |
| 50 aPa | 5e-19 hPa |
| 100 aPa | 1e-18 hPa |
Reverse conversion: Hectopascal to Attopascal
1e-20 hPa × 1e+20 = 1 aPa
1e-20 hectopascals = 1 attopascals.
attopascals = hectopascals × 1e+20
For a page dedicated to this direction, see Hectopascal to Attopascal.
Understanding the Attopascal (aPa)
Attopascal is 1e-18 pascal units.
Understanding the Hectopascal (hPa)
Hectopascal is 100 pascal units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many hectopascals are in 1 attopascal?
1 attopascal equals 1e-20 hectopascals, using the exact defined conversion factor rather than an estimate.
How do I convert attopascal to hectopascal?
Multiply the attopascal value by 1e-20. The converter above does this instantly to whatever precision you set.
How do I convert hectopascal back to attopascal?
Use the reverse factor: 1 hectopascal equals 1e+20 attopascals. You can also use the swap control in the converter above to flip the direction instantly.
What is a attopascal?
Attopascal (aPa) is a unit of pressure.
What is a hectopascal?
Hectopascal (hPa) is a unit of pressure.
Is the attopascal to hectopascal conversion exact?
Yes. Both attopascal and hectopascal are defined by fixed standards rather than physical artifacts, so the factor of 1e-20 used above is exact to as many digits as you choose to display.