Bar to Atmospheres Converter
Convert bar to standard atmospheres — one bar is 0.9869 atm, close to sea-level pressure but not equal to it. Results update as you type; exact factors shown.
One bar is 0.9869 standard atmospheres — see the exact factor, not a rounded rule of thumb.
How the bar to atmospheres 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 bar | 0.4935 atm | bars to standard atmospheres |
| 1 bar | 0.9869 atm | bar to standard atmospheres |
| 1.0133 bar | 1 atm | bars to standard atmospheres |
| 1.5 bar | 1.4804 atm | bars to standard atmospheres |
| 2 bar | 1.9738 atm | bars to standard atmospheres |
| 2.5 bar | 2.4673 atm | bars to standard atmospheres |
| 3 bar | 2.9608 atm | bars to standard atmospheres |
| 5 bar | 4.9346 atm | bars to standard atmospheres |
| 10 bar | 9.8692 atm | bars to standard atmospheres |
| 50 bar | 49.3462 atm | bars to standard atmospheres |
| 100 bar | 98.6923 atm | bars to standard atmospheres |
| 200 bar | 197.3847 atm | bars to standard atmospheres |
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
Is one bar the same as one atmosphere?
Almost, but not exactly — 1 bar is 0.98692 atm. A standard atmosphere is 1.01325 bar.
Why do the two units differ?
The atmosphere was defined from average sea-level pressure; the bar was defined as a round 100,000 pascals.
What is 2 bar in atm?
1.974 atm.
Which unit do scuba divers use?
Bar almost everywhere, because each 10 m of sea water adds very nearly 1 bar.
What is 200 bar in atm?
197.4 atm — a typical full scuba cylinder.
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.