Pressure converter
Atmospheres to Bar
If you need to know how many Bar one Atmospheres contains, the answer is 1.01325. The conversion is linear, so 10 atm is 10.1325 bar and 100 atm is 101.325 bar. Use the converter for any other value.
Formula 1 atm = 1.01325 bar
Need the other direction? Bar to Atmospheres.
How to convert Atmospheres to Bar
Standard atmosphere is exactly 101,325 pascals. One bar is exactly 100,000 pascals, slightly below standard atmosphere.
To convert Atmospheres to Bar, multiply the value in atm by 1.01325. For example, 10 atm × 1.01325 = 10.1325 bar. This works because the ratio between the two units is constant for every value in pressure.
Worked examples
| atm | bar |
|---|---|
| 1 atm | 1.01325 bar |
| 2.5 atm | 2.533125 bar |
| 5 atm | 5.06625 bar |
| 10 atm | 10.1325 bar |
| 25 atm | 25.33125 bar |
| 50 atm | 50.6625 bar |
| 100 atm | 101.325 bar |
Reverse conversion
| bar | atm |
|---|---|
| 1 bar | 0.98692327 atm |
| 5 bar | 4.934616 atm |
| 10 bar | 9.869233 atm |
| 25 bar | 24.673082 atm |
| 50 bar | 49.346163 atm |
| 100 bar | 98.692327 atm |
When this conversion is useful
This is the calculation you need when you are inflating a tyre, reading a barometer or checking an engineering spec. Because the factor is fixed, you can use the same number for a single measurement or for a batch: 1,000 atm is 1,013.25 bar.
Is the conversion exact?
Yes for practical use: the factors come from international definitions, with rounding applied only for display.
Reference: BIPM SI Brochure and NIST SP 811. Last reviewed: 2026-11-01.
atm to bar conversion chart
The chart lists the most requested values. For a value that is not here, use the converter at the top of the page.
| Atmospheres (atm) | Bar (bar) |
|---|---|
| 1 atm | 1.01325 bar |
| 2 atm | 2.0265 bar |
| 3 atm | 3.03975 bar |
| 4 atm | 4.053 bar |
| 5 atm | 5.06625 bar |
| 6 atm | 6.0795 bar |
| 7 atm | 7.09275 bar |
| 8 atm | 8.106 bar |
| 9 atm | 9.11925 bar |
| 10 atm | 10.1325 bar |
| 11 atm | 11.14575 bar |
| 12 atm | 12.159 bar |
| 13 atm | 13.17225 bar |
| 14 atm | 14.1855 bar |
| 15 atm | 15.19875 bar |
| 16 atm | 16.212 bar |
| 17 atm | 17.22525 bar |
| 18 atm | 18.2385 bar |
| 19 atm | 19.25175 bar |
| 20 atm | 20.265 bar |
| 21 atm | 21.27825 bar |
| 22 atm | 22.2915 bar |
| 23 atm | 23.30475 bar |
| 24 atm | 24.318 bar |
| 25 atm | 25.33125 bar |
| 26 atm | 26.3445 bar |
| 27 atm | 27.35775 bar |
| 28 atm | 28.371 bar |
| 29 atm | 29.38425 bar |
| 30 atm | 30.3975 bar |
| 31 atm | 31.41075 bar |
| 32 atm | 32.424 bar |
| 33 atm | 33.43725 bar |
| 34 atm | 34.4505 bar |
| 35 atm | 35.46375 bar |
| 36 atm | 36.477 bar |
| 37 atm | 37.49025 bar |
| 38 atm | 38.5035 bar |
| 39 atm | 39.51675 bar |
| 40 atm | 40.53 bar |
| 41 atm | 41.54325 bar |
| 42 atm | 42.5565 bar |
| 43 atm | 43.56975 bar |
| 44 atm | 44.583 bar |
| 45 atm | 45.59625 bar |
| 46 atm | 46.6095 bar |
| 47 atm | 47.62275 bar |
| 48 atm | 48.636 bar |
| 49 atm | 49.64925 bar |
| 50 atm | 50.6625 bar |
| 60 atm | 60.795 bar |
| 70 atm | 70.9275 bar |
| 80 atm | 81.06 bar |
| 90 atm | 91.1925 bar |
| 100 atm | 101.325 bar |
Frequently asked questions
How many Bar are in 1 Atmospheres?
1 atm equals 1.01325 bar.
How do I convert Atmospheres to Bar?
Multiply the atm value by 1.01325. Example: 25 atm = 25.33125 bar.
What is 2.5 atm in bar?
2.5 atm = 2.533125 bar.
Is the atm to bar conversion exact?
Yes for practical use: the factors come from international definitions, with rounding applied only for display.
Does the calculator work offline?
Yes. The conversion runs in your browser with JavaScript, so it works after the page has loaded, even without a connection.