In 1 atmospheres there are 1.01325 bars. Meanwhile in 1 bars there are 0.986923 atmospheres. Keep reading to learn more about each unit of measure and how they are calculated. Or just use the Bars to Atmospheres calculator above to convert any number.
* Values rounded to 6 decimal places for readability
To convert atmospheres (atm) to bars (bar), multiply the atm value by 1.01325.
Example:
For quick mental math, you can treat 1 atm as about 1.01 bar for a close estimate.
An atmosphere (atm) is a common unit of pressure. It matches average air pressure at sea level. In exact terms, 1 atm equals 101,325 pascals (Pa).
A bar is another unit of pressure used in science and industry. It is close to atmospheric pressure but not the same. In exact terms, 1 bar equals 100,000 Pa.
Multiply atmospheres by 1.01325 to get bars.
Formula: bar = atm × 1.01325
1 atm equals 1.01325 bar. This comes from the exact pascal values for each unit.
1 bar equals about 0.986923 atm.
Formula: atm = bar ÷ 1.01325
They are based on different reference values.
atm is higher than bar.
Since 1 atm = 1.01325 bar, an atmosphere is slightly more pressure than a bar.
Use bar = atm × 1.01325.
Use a quick estimate. Add about 1.3% to the atm value.
Example: 10 atm is about 10 + 0.13 = 10.13 bar (very close to 10.1325).
Both units show up in pressure readings.
No. The conversion is a fixed unit change. Temperature can change the pressure of a gas, but it doesn’t change how atm and bar relate.
No. ata means “atmospheres absolute.” It includes ambient pressure. atm is a unit and can describe absolute or gauge pressure depending on context. Always confirm whether your pressure is absolute or gauge before you compare values.
bar is absolute pressure unless stated otherwise. barg means “bar gauge,” which is pressure above local air pressure.
A common relation at sea level:
Use the same unit conversion: bar = atm × 1.01325. Then check if the rating uses absolute pressure or gauge pressure. Dive terms can mix both, so the label matters.
It depends on the job. For many uses, 1 atm ≈ 1.01 bar is fine. For lab or engineering work, use the full factor 1.01325 for better accuracy.
The Calculate Box tool to convert atmospheres to bars uses the open source script Convert.js to convert units of measurement. To use this tool, simply type a atmospheres value in the box and have it instantly converted to bars.