A bar is exactly 100,000 pascals.
Bars to Millibars Converter — bar to mbar
Convert Bar (bar) to Millibar (mbar) using the exact conversion factor (1 bar = 1,000 millibar). See the formula, worked examples, conversion table, history, and common uses.
Bars to Millibars converter
Converter
Pressure Converter
Convert pascals, bars, PSI, atmospheres, mercury columns, water columns, and engineering pressure units.
Context values
Some unit families need one extra value for a physically accurate result.
A millibar is 100 pascals.
Result = input x 100000 / 100.
Pressure uses the pascal as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Bars to Millibars
Bar and Millibar both show up on pressure gauges — psi is standard on US tire and tool specifications, while bar is the everyday pressure unit across most of the rest of the world. Bar is most often used for tire pressure specifications outside the us.
Formula
millibars = bars × 1000
This factor comes from each unit's defined relationship to the category's base unit: 1 bar equals 100000 base units, and 1 millibar equals 100 base units, so dividing one by the other gives the direct bar-to-millibar factor of 1000.
Simple example
1 bar × 1000 = 1,000 mbar
1 bar = 1,000 millibars.
Real-world example
35 bar × 1000 = 35,000 mbar
35 bars = 35,000 millibars.
Conversion table
| Bar (bar) | Millibar (mbar) |
|---|---|
| 1 bar | 1,000 mbar |
| 5 bar | 5,000 mbar |
| 10 bar | 10,000 mbar |
| 25 bar | 25,000 mbar |
| 50 bar | 50,000 mbar |
| 100 bar | 100,000 mbar |
Reverse conversion: Millibar to Bar
1 mbar × 0.001 = 0.001 bar
1 millibar = 0.001 bars.
bars = millibars × 0.001
For a page dedicated to this direction, see Millibar to Bar.
Understanding the Bar
Bar (bar) measures pressure. A bar is defined as exactly 100,000 pascals, close to (but distinct from) one standard atmosphere (101,325 Pa). It is classified as a Non-SI metric unit accepted for use with SI.
Where it's used: Widely used in Europe and most of the world for tire pressure, weather, and industrial pressure
Uses of the Bar today
- Tire pressure specifications outside the US
- Meteorology (weather maps commonly use millibars, hPa)
- Industrial and hydraulic pressure ratings in metric-system countries
History of the Bar
The bar was proposed by Norwegian meteorologist Vilhelm Bjerknes around 1906 as a convenient round pressure unit close to atmospheric pressure, derived from the CGS unit system (one bar equals one million dynes per square centimeter).
Though not an SI unit, the bar remains in wide practical use, particularly in meteorology (as the millibar, now more often written as the equivalent hectopascal) and in tire and hydraulic pressure specifications across most of the world.
Historical origin. Bar was not the invention of a single named person; it developed through the process described above.
Understanding the Millibar (mbar)
A millibar is 100 pascals.
Bar — sources
- BIPM SI Brochure — Non-SI units accepted for use with SI — Lists the bar among accepted non-SI pressure units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many millibars are in 1 bar?
1 bar equals 1,000 millibars, using the exact defined conversion factor rather than an estimate.
How do I convert bar to millibar?
Multiply the bar value by 1000. The converter above does this instantly to whatever precision you set.
How do I convert millibar back to bar?
Use the reverse factor: 1 millibar equals 0.001 bars. You can also use the swap control in the converter above to flip the direction instantly.
What is a bar?
Bar (bar) measures pressure. A bar is defined as exactly 100,000 pascals, close to (but distinct from) one standard atmosphere (101,325 Pa). It is classified as a Non-SI metric unit accepted for use with SI.
What is a millibar?
Millibar (mbar) is a unit of pressure.
Is the bar to millibar conversion exact?
Yes. A bar is defined as exactly 100,000 pascals, close to (but distinct from) one standard atmosphere (101,325 Pa). That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
Where is the bar still used today?
Widely used in Europe and most of the world for tire pressure, weather, and industrial pressure