mbar to atm Converter

How to convert millibars to atmospheres

Formulaatm = mbar × 0.0009869232667

Because one standard atmosphere equals 1,013.25 millibars, you can also divide: atm = mbar ÷ 1,013.25.

A millibar is smaller than a standard atmosphere: it takes 1,013.25 millibars to make one standard atmosphere.

Worked examples

1 millibar1 mbar × 0.0009869232667 = 0.0009869232667 atm
5 millibars5 mbar × 0.0009869232667 = 0.004934616334 atm
10 millibars10 mbar × 0.0009869232667 = 0.009869232667 atm
20 millibars20 mbar × 0.0009869232667 = 0.01973846533 atm
100 millibars100 mbar × 0.0009869232667 = 0.09869232667 atm

Millibars to atmospheres conversion table

Values are calculated by the conversion engine and rounded to 8 significant figures.

Millibars to atmospheres: 0.1–10 mbar
Millibars (mbar)	Atmospheres (atm)
0.1 mbar	0.000098692327 atm
0.25 mbar	0.00024673082 atm
0.5 mbar	0.00049346163 atm
1 mbar	0.00098692327 atm
2 mbar	0.0019738465 atm
3 mbar	0.0029607698 atm
4 mbar	0.0039476931 atm
5 mbar	0.0049346163 atm
6 mbar	0.0059215396 atm
7 mbar	0.0069084629 atm
8 mbar	0.0078953861 atm
9 mbar	0.0088823094 atm
10 mbar	0.0098692327 atm

Millibars to atmospheres: 12–1,000 mbar
Millibars (mbar)	Atmospheres (atm)
12 mbar	0.011843079 atm
15 mbar	0.014803849 atm
20 mbar	0.019738465 atm
25 mbar	0.024673082 atm
30 mbar	0.029607698 atm
40 mbar	0.039476931 atm
50 mbar	0.049346163 atm
75 mbar	0.074019245 atm
100 mbar	0.098692327 atm
250 mbar	0.24673082 atm
500 mbar	0.49346163 atm
1,000 mbar	0.98692327 atm

About the units

Millibar (mbar)

The millibar (mbar) is a unit of pressure in the metric system. One millibar equals 100 pascals (Pa).

Standard atmosphere (atm)

Exactly 101,325 Pa — average sea-level air pressure.

Frequently asked questions

How many atmospheres are in one millibar?

There are 0.0009869232667 atmospheres in one millibar, and this value is exact by definition.

How do I convert millibars to atmospheres?

Multiply the number of millibars by 0.0009869232667. For example, 10 mbar × 0.0009869232667 = 0.009869232667 atm.

How many millibars are in one standard atmosphere?

One standard atmosphere equals 1,013.25 millibars. That is the reverse factor, 1 ÷ 0.0009869232667.

What is 10 millibars in atmospheres?

10 mbar = 0.009869232667 atm.

Is this mbar to atm converter accurate?

Yes. Both units are defined exactly in terms of SI units, so the conversion factor is exact; results are shown to 12 significant figures by default and you can change precision in the converter. Calculations run in your browser using the same tested engine that generated this page.