A standard atmosphere is exactly 101,325 pascals.
Atmospheres to Megapascals Converter — atm to MPa
Convert Atmosphere (atm) to Megapascal (MPa) using the exact conversion factor (1 atmosphere = 0.101325 megapascal). See the formula, worked examples, conversion table, and common uses.
Atmospheres to Megapascals 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.
Megapascal is 1000000 pascal units.
Result = input x 101325 / 1e+6.
Pressure uses the pascal as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Atmospheres to Megapascals
Atmosphere and Megapascal 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
megapascals = atmospheres × 0.101325
This factor comes from each unit's defined relationship to the category's base unit: 1 atmosphere equals 101325 base units, and 1 megapascal equals 1000000 base units, so dividing one by the other gives the direct atmosphere-to-megapascal factor of 0.101325.
Simple example
1 atm × 0.101325 = 0.101325 MPa
1 atmosphere = 0.101325 megapascals.
Real-world example
35 atm × 0.101325 = 3.546375 MPa
35 atmospheres = 3.546375 megapascals.
Conversion table
| Atmosphere (atm) | Megapascal (MPa) |
|---|---|
| 1 atm | 0.101325 MPa |
| 5 atm | 0.506625 MPa |
| 10 atm | 1.01325 MPa |
| 25 atm | 2.533125 MPa |
| 50 atm | 5.06625 MPa |
| 100 atm | 10.1325 MPa |
Reverse conversion: Megapascal to Atmosphere
0.101325 MPa × 9.869232667 = 1 atm
0.101325 megapascals = 1 atmosphere.
atmospheres = megapascals × 9.86923266716
For a page dedicated to this direction, see Megapascal 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 Megapascal (MPa)
Megapascal is 1000000 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 megapascals are in 1 atmosphere?
1 atmosphere equals 0.101325 megapascals, using the exact defined conversion factor rather than an estimate.
How do I convert atmosphere to megapascal?
Multiply the atmosphere value by 0.101325. The converter above does this instantly to whatever precision you set.
How do I convert megapascal back to atmosphere?
Use the reverse factor: 1 megapascal equals 9.869232667 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 megapascal?
Megapascal (MPa) is a unit of pressure.
Is the atmosphere to megapascal 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