Atmospheres to Bar Converter
Convert standard atmospheres to bar — one atmosphere is exactly 1.01325 bar. Results update as you type; exact factors shown.
One standard atmosphere is 1.0133 bars — see the exact factor, not a rounded rule of thumb.
How the atmospheres to bar converter works
Pressures convert through the pascal (1 N/m²). One bar is exactly 100 kPa; a standard atmosphere is exactly 101.325 kPa; 1 psi is 6.894757 kPa (a pound-force on a square inch); 1 mmHg is 133.322 Pa by the conventional definition.
Australia is fully metric under the National Measurement Act 1960; imperial units appear only in trade with the US and in older documents.
Common pressure conversions
| From | To | Units |
|---|---|---|
| 0.5 atm | 0.5066 bar | standard atmospheres to bars |
| 1 atm | 1.0133 bar | standard atmosphere to bars |
| 1.5 atm | 1.5199 bar | standard atmospheres to bars |
| 2 atm | 2.0265 bar | standard atmospheres to bars |
| 3 atm | 3.0398 bar | standard atmospheres to bars |
| 5 atm | 5.0663 bar | standard atmospheres to bars |
| 10 atm | 10.1325 bar | standard atmospheres to bars |
| 20 atm | 20.265 bar | standard atmospheres to bars |
| 50 atm | 50.6625 bar | standard atmospheres to bars |
| 100 atm | 101.325 bar | standard atmospheres to bars |
| 150 atm | 151.9875 bar | standard atmospheres to bars |
| 200 atm | 202.65 bar | standard atmospheres to bars |
Units in this converter and their exact factors
| Unit | Symbol | One unit in pascals |
|---|---|---|
| pascal | Pa | 1 pascal |
| kilopascal | kPa | 1,000 pascal |
| megapascal | MPa | 1,000,000 pascal |
| bar | bar | 100,000 pascal |
| millibar (hectopascal) | mbar | 100 pascal |
| standard atmosphere | atm | 101,325 pascal |
| pound per square inch | psi | 6,894.757293168 pascal |
| millimetre of mercury | mmHg | 133.322387415 pascal |
| inch of mercury | inHg | 3,386.389 pascal |
FAQFrequently asked questions about pressure conversion
How many bar in one atmosphere?
Exactly 1.01325 bar, by definition.
Why is the atmosphere not a round number of bar?
Because the two were defined independently — the atmosphere from measured sea-level pressure, the bar as 100 kPa exactly.
What is 10 atm in bar?
10.1325 bar.
Which is used in science?
The pascal and its multiples; the atmosphere survives mainly in chemistry and the bar in engineering and diving.
Is 1 atm the pressure at sea level?
It is the standard reference for it. Real sea-level pressure varies roughly 0.95 to 1.05 atm with the weather.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Measurement Institute (NMI) — Australia's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.