Convert Millibars to Atmospheres

Enter the pressure in millibars below to get the value converted to atmospheres.

Results in Atmospheres:
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1 mbar = 0.000987 atm

How to Convert Millibars to Atmospheres

Calculators can be used to convert measurements from one unit to another

To convert a millibar measurement to a atmosphere measurement, multiply the pressure by the conversion ratio. One millibar is equal to 0.000987 atmospheres, so use this simple formula to convert:

atmospheres = millibars × 0.000987

The pressure in atmospheres is equal to the millibars multiplied by 0.000987.

For example, here's how to convert 5 millibars to atmospheres using the formula above.
5 mbar = (5 × 0.000987) = 0.004935 atm

Millibars and atmospheres are both units used to measure pressure. Keep reading to learn more about each unit of measure.


One millibar is equal to one-thousandth of a bar, which is defined as the pressure of one newton per square meter. One millibar is also equal to one hectopascal.

The millibar is a non-SI metric unit for pressure. In the metric system, "milli" is the prefix for 10-3. Millibars can be abbreviated as mbar, for example 1 millibar can be written as 1 mbar.


The atmosphere is a reference measure of pressure equal to 101,325 pascals or 1,013,250 dynes. The atmosphere was originally defined as the pressure of 760 millimeters of mercury at standard gravity at 0 °C, but was later redefined in 1954 to be equal to 1,013,250 dynes.

Atmospheres can be abbreviated as atm, for example 1 atmosphere can be written as 1 atm.

Millibar Measurements and Equivalent Atmosphere Conversions

Common millibar values converted to the equivalent atmosphere value
Millibars Atmospheres
1 mbar 0.000987 atm
2 mbar 0.001974 atm
3 mbar 0.002961 atm
4 mbar 0.003948 atm
5 mbar 0.004935 atm
6 mbar 0.005922 atm
7 mbar 0.006908 atm
8 mbar 0.007895 atm
9 mbar 0.008882 atm
10 mbar 0.009869 atm
11 mbar 0.010856 atm
12 mbar 0.011843 atm
13 mbar 0.01283 atm
14 mbar 0.013817 atm
15 mbar 0.014804 atm
16 mbar 0.015791 atm
17 mbar 0.016778 atm
18 mbar 0.017765 atm
19 mbar 0.018752 atm
20 mbar 0.019738 atm
21 mbar 0.020725 atm
22 mbar 0.021712 atm
23 mbar 0.022699 atm
24 mbar 0.023686 atm
25 mbar 0.024673 atm
26 mbar 0.02566 atm
27 mbar 0.026647 atm
28 mbar 0.027634 atm
29 mbar 0.028621 atm
30 mbar 0.029608 atm
31 mbar 0.030595 atm
32 mbar 0.031582 atm
33 mbar 0.032568 atm
34 mbar 0.033555 atm
35 mbar 0.034542 atm
36 mbar 0.035529 atm
37 mbar 0.036516 atm
38 mbar 0.037503 atm
39 mbar 0.03849 atm
40 mbar 0.039477 atm

More Millibar Pressure Conversions

Convert to Pascals
1 mbar is equal to 100 pascals
Convert to Hectopascals
1 mbar is equal to 1 hectopascals
Convert to Bars
1 mbar is equal to 0.001 bars
Convert to Kilograms Per Square Centimeter
1 mbar is equal to 0.00102 kilograms per square centimeter
Convert to Kilograms Per Square Meter
1 mbar is equal to 10.197162 kilograms per square meter
Convert to Pounds Per Square Inch
1 mbar is equal to 0.014504 pounds per square inch
Convert to Pounds Per Square Foot
1 mbar is equal to 2.088546 pounds per square foot
Convert to Torr
1 mbar is equal to 0.750062 torr

Unit of Measurement Conversion Made Easy!

There are thousands of units of measure in use across the globe, and converting from one to another can be very difficult since each conversion requires a different formula to derive the result. Our unit of measurement conversion tools are meant to be dead easy. We break the mold of the typical dry and complicated experience. In addition to converting from one measurement to another, we provide the formula so you can see how the conversion is done, use it on you’re own calculator if you need to!

Convert units of length, weight, volume, and area between imperial and metric measures

Understanding the Metric System

The metric system makes it relatively easy to convert from one metric unit to another metric unit. The metric system uses a base unit, think meters or grams, and a prefix such as kilo or milli. The prefixes differ from the base units by differing powers of 10. So to convert within the metric system it’s usually a matter of multiplying or dividing by one of the powers of 10.

Here is a list of some of the common metric prefixes:

  • “kilo” – 1,000x larger
  • “hecto” – 100x larger
  • “deca” – 10x larger
  • “deci” – 10x smaller
  • “centi” – 100x smaller
  • “milli” – 1,000x smaller

There is a helpful mnemonic for remembering the prefixes: “King Henry Died Until Drinking Chocolate Milk.”
The u in Until refers to the base unit.