Attopascal is 1e-18 pascal units.
Attopascals to Millibars Converter — aPa to mbar
Convert Attopascal (aPa) to Millibar (mbar) using the exact conversion factor (1 attopascal = 1e-20 millibar). See the formula, worked examples, and conversion table.
Attopascals to Millibars 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.
A millibar is 100 pascals.
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 Millibars
Attopascal and Millibar 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 a millibar is 100 pascals.
Formula
millibars = 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 millibar equals 100 base units, so dividing one by the other gives the direct attopascal-to-millibar factor of 1e-20.
Simple example
1 aPa × 1e-20 = 1e-20 mbar
1 attopascal = 1e-20 millibars.
Real-world example
35 aPa × 1e-20 = 3.5e-19 mbar
35 attopascals = 3.5e-19 millibars.
Conversion table
| Attopascal (aPa) | Millibar (mbar) |
|---|---|
| 1 aPa | 1e-20 mbar |
| 5 aPa | 5e-20 mbar |
| 10 aPa | 1e-19 mbar |
| 25 aPa | 2.5e-19 mbar |
| 50 aPa | 5e-19 mbar |
| 100 aPa | 1e-18 mbar |
Reverse conversion: Millibar to Attopascal
1e-20 mbar × 1e+20 = 1 aPa
1e-20 millibars = 1 attopascals.
attopascals = millibars × 1e+20
For a page dedicated to this direction, see Millibar to Attopascal.
Understanding the Attopascal (aPa)
Attopascal is 1e-18 pascal units.
Understanding the Millibar (mbar)
A millibar is 100 pascals.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many millibars are in 1 attopascal?
1 attopascal equals 1e-20 millibars, using the exact defined conversion factor rather than an estimate.
How do I convert attopascal to millibar?
Multiply the attopascal value by 1e-20. The converter above does this instantly to whatever precision you set.
How do I convert millibar back to attopascal?
Use the reverse factor: 1 millibar 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 millibar?
Millibar (mbar) is a unit of pressure.
Is the attopascal to millibar conversion exact?
Yes. Both attopascal and millibar 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.