A standard atmosphere is exactly 101,325 pascals.
Atmospheres to Attopascals Converter — atm to aPa
Convert Atmosphere (atm) to Attopascal (aPa) using the exact conversion factor (1 atmosphere = 1.01325e+23 attopascal). See the formula, worked examples, conversion table, and common uses.
Atmospheres to Attopascals 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.
Attopascal is 1e-18 pascal units.
Result = input x 101325 / 1e-18.
Pressure uses the pascal as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Atmospheres to Attopascals
Atmosphere and Attopascal 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. Atmosphere is most often used for chemistry (standard conditions are often defined at 1 atm).
Formula
attopascals = atmospheres × 1.01325e+23
This factor comes from each unit's defined relationship to the category's base unit: 1 atmosphere equals 101325 base units, and 1 attopascal equals 1e-18 base units, so dividing one by the other gives the direct atmosphere-to-attopascal factor of 1.01325e+23.
Simple example
1 atm × 1.01325e+23 = 1.01325e+23 aPa
1 atmosphere = 1.01325e+23 attopascals.
Real-world example
35 atm × 1.01325e+23 = 3.546375e+24 aPa
35 atmospheres = 3.546375e+24 attopascals.
Conversion table
| Atmosphere (atm) | Attopascal (aPa) |
|---|---|
| 1 atm | 1.01325e+23 aPa |
| 5 atm | 5.06625e+23 aPa |
| 10 atm | 1.01325e+24 aPa |
| 25 atm | 2.533125e+24 aPa |
| 50 atm | 5.06625e+24 aPa |
| 100 atm | 1.01325e+25 aPa |
Reverse conversion: Attopascal to Atmosphere
1.01325e+23 aPa × 9.869233e-24 = 1 atm
1.01325e+23 attopascals = 1 atmosphere.
atmospheres = attopascals × 9.869233e-24
For a page dedicated to this direction, see Attopascal to Atmosphere.
Understanding the Atmosphere
Atmosphere (atm) measures pressure. Defined as exactly 101,325 pascals, originally based on the average atmospheric pressure at mean sea level. It is classified as a non-SI unit accepted for use with the SI.
Where it's used: Widely used internationally in chemistry, meteorology, and diving/aviation contexts alongside the pascal and bar
Uses of the Atmosphere today
- Chemistry (standard conditions are often defined at 1 atm)
- Diving and aviation pressure references
- General reference for everyday atmospheric pressure
Understanding the Attopascal (aPa)
Attopascal is 1e-18 pascal units.
Atmosphere — sources
- BIPM SI Brochure — Standard atmosphere listed among non-SI units with a fixed exact value in pascals.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many attopascals are in 1 atmosphere?
1 atmosphere equals 1.01325e+23 attopascals, using the exact defined conversion factor rather than an estimate.
How do I convert atmosphere to attopascal?
Multiply the atmosphere value by 1.01325e+23. The converter above does this instantly to whatever precision you set.
How do I convert attopascal back to atmosphere?
Use the reverse factor: 1 attopascal equals 9.869233e-24 atmospheres. You can also use the swap control in the converter above to flip the direction instantly.
What is a atmosphere?
Atmosphere (atm) measures pressure. Defined as exactly 101,325 pascals, originally based on the average atmospheric pressure at mean sea level. It is classified as a non-SI unit accepted for use with the SI.
What is a attopascal?
Attopascal (aPa) is a unit of pressure.
Is the atmosphere to attopascal conversion exact?
Yes. Defined as exactly 101,325 pascals, originally based on the average atmospheric pressure at mean sea level. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
Where is the atmosphere still used today?
Widely used internationally in chemistry, meteorology, and diving/aviation contexts alongside the pascal and bar