How to Convert Millibars to Bar (mbar to bar)
Pressure conversions are used for tyre pressure (psi or bar), blood pressure readings in mmHg and weather maps in millibars. This guide shows how to convert millibars into bar by hand, with examples and a quick-reference table.
The conversion
To convert millibars to bar, multiply the value by 0.001. To go the other way, divide by the same number (or multiply by 1,000). For a quick estimate, multiply by about 0.001.
Bar = millibars × 0.001
Worked examples
- 3 mbar = 0.003 bar
- 12.5 mbar = 0.0125 bar
- 75 mbar = 0.075 bar
Millibars to Bar table
| Millibars | Bar |
|---|---|
| 1 mbar | 0.001 bar |
| 2 mbar | 0.002 bar |
| 5 mbar | 0.005 bar |
| 10 mbar | 0.01 bar |
| 20 mbar | 0.02 bar |
| 25 mbar | 0.025 bar |
| 50 mbar | 0.05 bar |
| 100 mbar | 0.1 bar |
| 250 mbar | 0.25 bar |
| 500 mbar | 0.5 bar |
| 1,000 mbar | 1 bar |
Common questions
Is mbar to bar exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Bar to Millibars converter.
Mistakes to avoid
Multiplying when you should divide
Converting to a smaller unit gives a bigger number, and converting to a larger unit gives a smaller one. If your answer moves the wrong way, you have inverted the factor.
Mixing similar-sounding units
US and imperial gallons, pints and tons are different sizes, and decimal kilobytes differ from binary kibibytes.
Rounding the factor too early
Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.
Background
Many conversion factors are exact by definition. The inch has been defined as exactly 2.54 centimetres since 1959, and the pound as exactly 0.45359237 kilograms, so conversions involving them can be as precise as you need.
Writing the units next to every number while you work is the simplest way to avoid mistakes. If the units do not cancel to leave the one you want, the calculation is set up wrongly.
For everyday use, three or four significant figures are usually enough. Engineering, science and trade documents may need more, and rounding should happen only at the end of a calculation.
For any value, use the Millibars to Bar Converter or browse all pressure converters.
Run your own numbers: Millibars to Bar Converter