Millibar to atmospheres converter
Convert millibar (mbar) to atmospheres (atm). Calculate a value, check the formula and compare common measurements.
Result for the values shown.
Calculations run in your browser.
What to enter
| Input | Meaning and units |
|---|---|
| Value | Enter value using the definition in the method and example. |
| From | Select the unit or currency in which the entered number is currently expressed. |
| To | Select the unit or currency you need for the answer. |
Understanding your result
The converted value describes the same pressure quantity in the selected target unit. Display rounding does not add precision to the original measurement.
Common mistakes
- Confusing the source and target units, or overlooking a prefix or case-sensitive symbol.
- Expecting a unit conversion to change gauge pressure into absolute pressure.
Check your calculation
- Convert to the target unit and then reverse the direction. Within display rounding, you should recover the original value.
Read the pressure measurement guide · Calculation checks, sources and review limits
How do I convert millibar to atmospheres?
Enter the value in millibar to find the same pressure quantity in atmospheres. The number changes to match the unit; the underlying quantity stays the same. Check the definitions below when a unit has more than one convention.
Common uses
- Interpret pressure specifications in a familiar unit.
- Compare pressure readings using consistent conventions.
How it works
For the displayed direction, 1 mbar equals 0.000986923266716 atm. The engine converts through the shared pressure base quantity. Atmospheres are standard atmospheres. Mercury-column factors use the conventional 0 °C definition; torr is 1/760 of a standard atmosphere. The multiplier is derived from the two centralized unit factors. Keep full precision until the final result; displayed answers use up to 12 significant digits.
Worked example
10 mbar converts to 0.00986923266716 atm. For the reverse direction, swap the units and enter 0.00986923266716 atm; the result is approximately 10 mbar.
FAQ
How do I convert mbar to atm?
atm = mbar × 0.000986923266716
Which definition is used?
Atmospheres are standard atmospheres. Mercury-column factors use the conventional 0 °C definition; torr is 1/760 of a standard atmosphere.
Common values
Use “Swap units” above for the reverse conversion. Values below are rounded to six significant digits.
| millibar | atmospheres |
|---|---|
| 1 | 0.000986923 |
| 5 | 0.00493462 |
| 10 | 0.00986923 |
| 20 | 0.0197385 |
| 30 | 0.0296077 |
| 50 | 0.0493462 |
| 100 | 0.0986923 |