Convert Millibar to Bar
1 millibar = 0.001 bar (bar). For example, 10 millibar = 0.01 bar and 100 millibar = 0.1 bar. Type any value below to convert millibar to bar both ways — it runs entirely in your browser.
Quick answer: Millibar to Bar
1 Millibar = 0.001 Bar (mbar → bar). To convert millibar to bar, multiply by 0.001. To convert bar to millibar, multiply by 1,000. The converter at the top does this instantly and both ways; the sections below give the formula, worked examples, a full conversion chart and answers to the most common millibar-to-bar questions.
How to convert Millibar to Bar
To convert millibar to bar, multiply the number of millibar by the conversion factor 0.001, because 1 mbar = 0.001 bar. The conversion is linear, so the same factor works for any value — whole numbers, decimals or fractions. For the reverse direction, 1 bar = 1,000 mbar, so you divide by 0.001 (or multiply by 1,000) to turn bar back into millibar.
bar = mbar × 0.001 ·
mbar = bar × 1,000
- Write down the value you want to convert, in millibar.
- Multiply it by 0.001.
- The result is the same area/length/quantity expressed in bar.
Millibar to Bar — worked examples
Each row shows the exact arithmetic so you can follow the conversion step by step. For example, 5 millibar is 0.005 bar because 5 mbar × 0.001 = 0.005 bar.
| Millibar | Calculation | Bar |
|---|---|---|
| 1 mbar | 1 mbar × 0.001 = 0.001 bar | 0.001 bar |
| 2 mbar | 2 mbar × 0.001 = 0.002 bar | 0.002 bar |
| 3 mbar | 3 mbar × 0.001 = 0.003 bar | 0.003 bar |
| 5 mbar | 5 mbar × 0.001 = 0.005 bar | 0.005 bar |
| 7 mbar | 7 mbar × 0.001 = 0.007 bar | 0.007 bar |
| 10 mbar | 10 mbar × 0.001 = 0.01 bar | 0.01 bar |
| 12 mbar | 12 mbar × 0.001 = 0.012 bar | 0.012 bar |
| 15 mbar | 15 mbar × 0.001 = 0.015 bar | 0.015 bar |
| 20 mbar | 20 mbar × 0.001 = 0.02 bar | 0.02 bar |
| 25 mbar | 25 mbar × 0.001 = 0.025 bar | 0.025 bar |
| 50 mbar | 50 mbar × 0.001 = 0.05 bar | 0.05 bar |
| 100 mbar | 100 mbar × 0.001 = 0.1 bar | 0.1 bar |
Common Millibar to Bar conversions
These are the millibar-to-bar values people look up most often. Every figure is computed from the exact factor, so you can rely on them for quick reference:
- 1 millibar = 0.001 bar
- 2 millibar = 0.002 bar
- 2.5 millibar = 0.0025 bar
- 3 millibar = 0.003 bar
- 4 millibar = 0.004 bar
- 5 millibar = 0.005 bar
- 6 millibar = 0.006 bar
- 7 millibar = 0.007 bar
- 8 millibar = 0.008 bar
- 9 millibar = 0.009 bar
- 10 millibar = 0.01 bar
- 12 millibar = 0.012 bar
- 15 millibar = 0.015 bar
- 20 millibar = 0.02 bar
- 25 millibar = 0.025 bar
- 30 millibar = 0.03 bar
- 50 millibar = 0.05 bar
- 75 millibar = 0.075 bar
- 100 millibar = 0.1 bar
- 200 millibar = 0.2 bar
- 500 millibar = 0.5 bar
- 1000 millibar = 1 bar
Millibar to Bar conversion chart (both directions)
The chart below converts millibar to bar and bar to millibar side by side, so it works whichever way you need. 1 millibar = 0.001 bar, and 1 bar = 1,000 millibar.
| Millibar → Bar | Bar → Millibar |
|---|---|
| 0.25 mbar = 0.00025 bar | 0.25 bar = 250 mbar |
| 0.5 mbar = 0.0005 bar | 0.5 bar = 500 mbar |
| 1 mbar = 0.001 bar | 1 bar = 1,000 mbar |
| 2 mbar = 0.002 bar | 2 bar = 2,000 mbar |
| 3 mbar = 0.003 bar | 3 bar = 3,000 mbar |
| 4 mbar = 0.004 bar | 4 bar = 4,000 mbar |
| 5 mbar = 0.005 bar | 5 bar = 5,000 mbar |
| 6 mbar = 0.006 bar | 6 bar = 6,000 mbar |
| 7 mbar = 0.007 bar | 7 bar = 7,000 mbar |
| 8 mbar = 0.008 bar | 8 bar = 8,000 mbar |
| 9 mbar = 0.009 bar | 9 bar = 9,000 mbar |
| 10 mbar = 0.01 bar | 10 bar = 10,000 mbar |
| 12 mbar = 0.012 bar | 12 bar = 12,000 mbar |
| 15 mbar = 0.015 bar | 15 bar = 15,000 mbar |
| 20 mbar = 0.02 bar | 20 bar = 20,000 mbar |
| 25 mbar = 0.025 bar | 25 bar = 25,000 mbar |
| 30 mbar = 0.03 bar | 30 bar = 30,000 mbar |
| 40 mbar = 0.04 bar | 40 bar = 40,000 mbar |
| 50 mbar = 0.05 bar | 50 bar = 50,000 mbar |
| 75 mbar = 0.075 bar | 75 bar = 75,000 mbar |
| 100 mbar = 0.1 bar | 100 bar = 100,000 mbar |
| 150 mbar = 0.15 bar | 150 bar = 150,000 mbar |
| 200 mbar = 0.2 bar | 200 bar = 200,000 mbar |
| 250 mbar = 0.25 bar | 250 bar = 250,000 mbar |
| 500 mbar = 0.5 bar | 500 bar = 500,000 mbar |
| 1000 mbar = 1 bar | 1000 bar = 1,000,000 mbar |
Millibar vs Bar: which is bigger?
A bar is the larger unit: one bar equals 1,000 millibars. Put another way, you need 1,000 millibars to make a single bar.
What is a Millibar? History, origin and usage
The bar and its millibar subdivision were proposed by the Norwegian meteorologist Vilhelm Bjerknes in the early twentieth century, as part of the same push that gave us modern weather fronts. He wanted a pressure unit sized to the atmosphere itself rather than to a mercury column, and the millibar was adopted internationally for weather work in 1929.
Millibars are still used for atmospheric pressure, especially in older records, in shipping and in some national forecasts. They also appear on vacuum equipment and altimeter settings. Because a millibar and a hectopascal are the same size, the two are freely interchangeable.
A millibar is one thousandth of a bar, or 100 pascals. The lowest sea-level pressure ever measured in a tropical cyclone was 870 mbar, in Typhoon Tip in 1979 — a reading that would be written identically as 870 hPa.
What is a Bar? History, origin and usage
The bar takes its name from the Greek báros, meaning weight. It was deliberately defined as exactly 100,000 pascals, a round number chosen to sit very close to average air pressure at sea level, so that a pressure "in bars" reads roughly as "how many atmospheres". It is not an SI unit, but the International Bureau of Weights and Measures lists it among the units accepted for use alongside SI.
Bars are the everyday pressure unit across most of Europe and much of Asia: tyre inflators, bicycle pumps, espresso machines, diving cylinders, pressure washers and boiler gauges. An espresso machine is conventionally built around 9 bar of brewing pressure.
A bar is close to, but not the same as, an atmosphere — one atmosphere is 1.01325 bar exactly, a difference of about 1.3%. Diving uses this closeness deliberately: seawater adds roughly one bar of pressure for every ten metres of depth.
Convert 1 Millibar to other units
It can help to see a millibar next to the other units it is commonly compared with. One millibar (mbar) is equal to:
| 1 Millibar equals | Unit |
|---|---|
| 100 Pa | Pascal |
| 1 hPa | Hectopascal |
| 0.1 kPa | Kilopascal |
| 0.0001 MPa | Megapascal |
| 0.001 bar | Bar |
| 0.0009869233 atm | Standard atmosphere |
| 0.7500617 Torr | Torr |
| 0.7500616 mmHg | Millimetre of mercury |
| 0.02952998 inHg | Inch of mercury |
| 10.19716 mmH₂O | Millimetre of water |
| 0.4014631 inH₂O | Inch of water |
| 0.01450377 psi | Pound per square inch |
| 0.001019716 kgf/cm² | Kilogram-force per square centimetre |
Convert 1 Bar to other units
One bar (bar) is equal to:
| 1 Bar equals | Unit |
|---|---|
| 100,000 Pa | Pascal |
| 1,000 hPa | Hectopascal |
| 100 kPa | Kilopascal |
| 0.1 MPa | Megapascal |
| 1,000 mbar | Millibar |
| 0.9869233 atm | Standard atmosphere |
| 750.0617 Torr | Torr |
| 750.0616 mmHg | Millimetre of mercury |
| 29.52998 inHg | Inch of mercury |
| 10,197.16 mmH₂O | Millimetre of water |
| 401.4631 inH₂O | Inch of water |
| 14.50377 psi | Pound per square inch |
| 1.019716 kgf/cm² | Kilogram-force per square centimetre |
Tips for converting Millibar to Bar
- To go from millibar to bar, multiply by 0.001; to go back, divide by 0.001 (or multiply by 1,000).
- For a quick mental estimate, remember that 1 millibar ≈ 0.001 bar, so 10 millibar ≈ 0.01 bar.
- The converter above keeps full precision; the tables round for readability, so use the tool for exact figures.
- Both fields update live as you type — change either side to convert in that direction.
How to use this Millibar to Bar converter
Type a number into the Millibar field and the equivalent in Bar appears instantly — there is no “convert” button to press and nothing is sent to a server, so it works offline once the page has loaded and is safe for any data. You can also type into the Bar field to convert the other way (bar to millibar). Use the swap control to flip the two units, and copy the result with a single click. Because the calculation runs in your browser with full floating-point precision, the converter is more exact than the rounded figures shown in the reference chart above — use the chart for quick look-ups and the tool for precise work.
Accuracy and method
Every figure on this page — the formula, the worked examples, the conversion chart and the “convert to other units” tables — is computed from a single verified conversion factor (1 mbar = 0.001 bar), never copied from a hand-typed lookup table that could drift. That factor is derived from each unit’s definition in terms of a common base unit, and an automated check re-verifies all of the site’s factors on every update, so the numbers here stay correct over time. This matters for millibar-to-bar conversions because a small rounding error in a published table compounds quickly at larger quantities; computing from the exact factor avoids that.
Sources
- BIPM — The International System of Units (SI Brochure) — the defining document for the SI, published by the International Bureau of Weights and Measures. It fixes the base unit that this conversion resolves to, which is why the factor here can be exact rather than approximate.
- NIST — Definitions of the SI base units — the US National Institute of Standards and Technology reference for the SI base units, used here as an independent cross-check on the base-unit definition.
Pressure factors here come from fixed definitions, anchored to the pascal: a bar is exactly 100,000 Pa, one atmosphere is exactly 101,325 Pa, a torr is exactly a 760th of an atmosphere, and psi is built from the exact pound and the exact inch. Two of them — psi and the torr — work out to decimals that repeat forever, so where a number is shown rounded it is marked, not quietly trimmed.
Frequently asked questions
- How many bar are in 1 millibar?
- 1 millibar = 0.001 bar (bar). To convert any number of millibar to bar, multiply by 0.001.
- How do I convert millibar to bar?
- Multiply the number of millibar by 0.001. For example, 10 millibar = 10 × 0.001 = 0.01 bar, and 25 millibar = 0.025 bar.
- How many millibar are in 1 bar?
- 1 bar = 1,000 millibar. So to convert bar back to millibar, multiply by 1,000.
- What is the formula to convert millibar to bar?
- bar = millibar × 0.001. The reverse formula is millibar = bar × 1,000.
- How much is 100 millibar in bar?
- 100 millibar = 0.1 bar. (And 1000 millibar = 1 bar.)
- Which is bigger, a millibar or a bar?
- A bar is larger: 1 bar = 1,000 millibar.
- Is this millibar to bar converter accurate?
- Yes — every value is computed from the exact 0.001 bar per mbar factor (not rounded look-up tables), and the factors are re-verified automatically on every update.
- Can I convert bar to millibar too?
- Yes. The converter works both ways — enter a value in either field. 1 bar = 1,000 millibar.