Convert Bars to Atmospheres
Convert Bars to Atmospheres instantly. 1 Bar (bar) equals 0.9869 Atmospheres (atm).
Bars to Atmospheres conversion table
| Bars (bar) | Atmospheres (atm) |
|---|---|
| 1 bar | 0.9869 atm |
| 2 bar | 1.9738 atm |
| 3 bar | 2.9608 atm |
| 5 bar | 4.9346 atm |
| 10 bar | 9.8692 atm |
| 20 bar | 19.7385 atm |
| 50 bar | 49.3462 atm |
| 100 bar | 98.6923 atm |
| 500 bar | 493.4616 atm |
| 1,000 bar | 986.9233 atm |
1 Bar = 0.9869 Atmospheres · multiply Bars by 0.9869
About converting Bars to Atmospheres
Bars (bar) and Atmospheres (atm) are both units of pressure, so converting between them is a single multiplication: multiply your Bars figure by 0.9869. Ten Bars comes to 9.8692 Atmospheres, and a hundred works out at 98.6923 Atmospheres.
Rule of thumb: going from Bars to Atmospheres divides, so the figure always shrinks — it takes about 1.0133 Bars to make a single Atmosphere. If your answer came out bigger, you have the conversion the wrong way round.
What is a Bar?
The bar is not an SI unit, but it is accepted for use alongside them, and it earns that place by sheer convenience: it was chosen to sit close to average atmospheric pressure, so "one bar" reads as roughly what the air is doing right now. It dominates European industry — compressed air, hydraulics, scuba cylinders, espresso machines and tyre pressures are all quoted in bar. Its subdivision the millibar had a long career in weather forecasting before being quietly replaced by the hectopascal, which is exactly the same size, so nothing on the old charts had to change.
What is an Atmosphere?
The standard atmosphere is a defined reference rather than a working unit: a figure fixed by agreement at roughly what the air presses at sea level on an ordinary day. Nobody sets a gauge to it. Instead it is the yardstick other pressures are described against — divers count depth in atmospheres, chemists specify reactions at one atmosphere, and test standards quote pressures as multiples of it. Because it is a defined number rather than a measured one, the real pressure outside almost never equals exactly one atmosphere; it wanders with the weather, which is what a barometer is telling you.
To put both in perspective: a scuba tank is filled to about 200 bar, while the pressure 10 metres underwater is about 2 atmospheres.
The converter above updates as you type, and the table lists common values for quick reference. Need the opposite direction? Use the Atmospheres to Bars converter, or browse all Pressure converters.
Frequently asked questions
How many Atmospheres are in one Bar?
There are 0.9869 Atmospheres in one Bar.
How do I convert Bars to Atmospheres?
Multiply the number of Bars by 0.9869. For example, 10 Bars = 9.8692 Atmospheres.
What is 100 Bars in Atmospheres?
100 Bars is equal to 98.6923 Atmospheres.
How do I convert Atmospheres to Bars?
Multiply the Atmospheres value by 1.0133 (or divide by 0.9869).
Is this Bars to Atmospheres conversion exact?
The definition is exact — Bars and Atmospheres are both fixed against the same base by international agreement — but the decimal shown here is rounded for readability, because the true ratio does not terminate. For engineering or scientific work, carry more decimal places than this page displays.
What is a Bar?
The bar is not an SI unit, but it is accepted for use alongside them, and it earns that place by sheer convenience: it was chosen to sit close to average atmospheric pressure, so "one bar" reads as roughly what the air is doing right now. It dominates European industry — compressed air, hydraulics, scuba cylinders, espresso machines and tyre pressures are all quoted in bar. Its subdivision the millibar had a long career in weather forecasting before being quietly replaced by the hectopascal, which is exactly the same size, so nothing on the old charts had to change.
What is an Atmosphere?
The standard atmosphere is a defined reference rather than a working unit: a figure fixed by agreement at roughly what the air presses at sea level on an ordinary day. Nobody sets a gauge to it. Instead it is the yardstick other pressures are described against — divers count depth in atmospheres, chemists specify reactions at one atmosphere, and test standards quote pressures as multiples of it. Because it is a defined number rather than a measured one, the real pressure outside almost never equals exactly one atmosphere; it wanders with the weather, which is what a barometer is telling you.