Atmospheres Converter
Convert Atmospheres (atm) to any other pressure unit. The table below gives the exact figure for each unit, and every conversion is worked from the same engine as the converter.
What atmospheres convert to
One atm in every other pressure unit.
| Unit | 1 atm | Reverse |
|---|---|---|
| Pascals | 101,325 Pa | 9.8692e-6 atm |
| Kilopascals | 101.325 kPa | 0.009869 atm |
| Megapascals | 0.101325 MPa | 9.869233 atm |
| Bar | 1.01325 bar | 0.986923 atm |
| Millibar | 1,013.25 mbar | 9.8692e-4 atm |
| Pounds per square inch | 14.695949 psi | 0.068046 atm |
| Millimeters of mercury | 759.999892 mmHg | 0.001316 atm |
| Inches of mercury | 29.921252 inHg | 0.033421 atm |
Multiply a atmospheres figure by the figure in the second column to get the unit in the first, or multiply by the third column to go the other way.
Atmospheres conversion reference
Atmospheres to Pascals
One atmospheres is 101,325 pascals, and one pascals is 9.8692e-6 atmospheres.
The pascal is the SI unit of pressure: one newton per square meter. It is used in science and engineering, usually as kilopascals or megapascals.
- 1 atm= 101,325 Pa
- 2 atm= 202,650 Pa
- 5 atm= 506,625 Pa
Atmospheres to Kilopascals
One atmospheres is 101.325 kilopascals, and one kilopascals is 0.009869 atmospheres.
A kilopascal is 1,000 pascals. It is the unit for tyre pressure in metric countries, and is used for gas and weather pressures.
- 1 atm= 101.325 kPa
- 2 atm= 202.65 kPa
- 5 atm= 506.625 kPa
Atmospheres to Megapascals
One atmospheres is 0.101325 megapascals, and one megapascals is 9.869233 atmospheres.
A megapascal is 1,000 kilopascals, or one million pascals. It is used for concrete strength, where structural concrete is typically specified between 20 and 40 MPa.
- 1 atm= 0.101325 MPa
- 2 atm= 0.20265 MPa
- 5 atm= 0.506625 MPa
Atmospheres to Bar
One atmospheres is 1.01325 bar, and one bar is 0.986923 atmospheres.
One bar is exactly 100,000 pascals, slightly less than one atmosphere. It is used for tyre pressure, industrial gases and weather charts.
- 1 atm= 1.01325 bar
- 2 atm= 2.0265 bar
- 5 atm= 5.06625 bar
Atmospheres to Millibar
One atmospheres is 1,013.25 millibar, and one millibar is 9.8692e-4 atmospheres.
A millibar is 100 pascals, identical to the hectopascal used in weather reports. Average sea-level pressure is about 1,013 millibars.
- 1 atm= 1,013.25 mbar
- 2 atm= 2,026.5 mbar
- 5 atm= 5,066.25 mbar
Atmospheres to Pounds per square inch
One atmospheres is 14.695949 pounds per square inch, and one pounds per square inch is 0.068046 atmospheres.
One psi (pound per square inch) is 6,894.757293168 pascals. It is the tyre-pressure and hydraulic unit in the United States and the UK.
- 1 atm= 14.695949 psi
- 2 atm= 29.391898 psi
- 5 atm= 73.479744 psi
Atmospheres to Millimeters of mercury
One atmospheres is 759.999892 millimeters of mercury, and one millimeters of mercury is 0.001316 atmospheres.
One millimeter of mercury is 133.322387415 pascals. It is still used for blood-pressure readings, where 120/80 mmHg is the familiar healthy range.
- 1 atm= 759.999892 mmHg
- 2 atm= 1,519.999783 mmHg
- 5 atm= 3,799.999459 mmHg
Atmospheres to Inches of mercury
One atmospheres is 29.921252 inches of mercury, and one inches of mercury is 0.033421 atmospheres.
One inch of mercury is 3,386.389 pascals. It is used for barometric pressure and altimeter settings in aviation in the United States.
- 1 atm= 29.921252 inHg
- 2 atm= 59.842505 inHg
- 5 atm= 149.606262 inHg
What atmospheres are used for
One atmosphere is exactly 101,325 pascals, the average air pressure at sea level. It is used for gas calculations and diving tables.
Bar, atmosphere and psi are exact definitions. Gauges and weather stations round heavily, so treat the last digit as indicative rather than precise.
Pressure units are all defined against the pascal, so the conversion is a multiplication by a fixed number. What makes this dimension awkward is that the numbers sit within tens of per cent of each other, so a small slip looks plausible.
Three of the units are close together on purpose: one bar is 100,000 pascals, one atmosphere is 101,325, and weather reports use millibars and hectopascals, which are the same size. A reading that looks like a unit error is often a genuine difference between gauge pressure and absolute pressure instead.
Checking a pressure conversion means converting through pascals and comparing with a known reference, such as the fact that a bar and an atmosphere differ by about 1.3%. The error to watch for is quoting a pressure without saying whether it is measured above atmospheric pressure or from a vacuum.
Atmospheres conversion tables
Atmospheres to Pascals
| Atmospheres (atm) | Pascals (Pa) |
|---|---|
| 1 | 101,325 |
| 2 | 202,650 |
| 3 | 303,975 |
| 4 | 405,300 |
| 5 | 506,625 |
| 10 | 1,013,250 |
| 25 | 2,533,125 |
| 50 | 5,066,250 |
| 100 | 10,132,500 |
Atmospheres to Kilopascals
| Atmospheres (atm) | Kilopascals (kPa) |
|---|---|
| 1 | 101.325 |
| 2 | 202.65 |
| 3 | 303.975 |
| 4 | 405.3 |
| 5 | 506.625 |
| 10 | 1,013.25 |
| 25 | 2,533.125 |
| 50 | 5,066.25 |
| 100 | 10,132.5 |
Atmospheres to Megapascals
| Atmospheres (atm) | Megapascals (MPa) |
|---|---|
| 1 | 0.101325 |
| 2 | 0.20265 |
| 3 | 0.303975 |
| 4 | 0.4053 |
| 5 | 0.506625 |
| 10 | 1.01325 |
| 25 | 2.533125 |
| 50 | 5.06625 |
| 100 | 10.1325 |