Select a category and enter your values below
To convert pressure from millibars (mbar) to millimeters of mercury (mmHg), multiply by 0.750062.
The factor comes from the definitions of the two units: 1 mbar is exactly 100 Pa, while 1 mmHg is 133.322 Pa (the pressure of a 1 mm column of mercury at 0 °C under standard gravity). Dividing 100 by 133.322 gives 0.750062 — conveniently close to ¾, which makes rough mental conversion easy: take three quarters of the millibar value.
The classic anchor point ties the two scales together:
A weather station reports a deep low-pressure system at 968 mbar. In mmHg:
Reverse direction: divide by 0.750062 (or multiply by 1.33322). A vacuum gauge showing 15 mmHg equals 20 mbar.
| mbar | mmHg |
|---|---|
| 1 | 0.75 |
| 100 | 75.01 |
| 500 | 375.03 |
| 750 | 562.55 |
| 1,000 | 750.06 |
| 1013.25 | 760.00 |
| 1,050 | 787.57 |
Meteorology settled on the millibar (identical to the hectopascal, hPa, that modern forecasts use), while mmHg survives in medicine and vacuum technique — blood pressure, respiratory therapy, freeze-drying and rotary-evaporator recipes are all written in mmHg or its synonym Torr. The conversion appears whenever these worlds touch: calibrating a medical vacuum regulator against a barometric reference, translating an old lab protocol to a modern digital gauge, or comparing aviation weather (hPa/mbar) with cabin-altitude physiology tables (mmHg). Since 1 mbar = 1 hPa exactly, this same page converts hPa to mmHg with no change to the factor.
How many millibar are in one millimeter of mercury? One millimeter of mercury (mmHg) contains 1.33322 millibar (mbar) — the inverse of the factor above. Multiplying by 0.7500637554192106329 takes you from millibar to millimeters of mercury; multiplying by 1.33322 brings you back.
Put in words: one millibar equals 0.7500637554192106329 millimeters of mercury, so the millibar is the smaller unit of this pair. Converting between them never changes the amount of pressure being measured — only the size of the unit you count it in.
A millibar (mbar) is a metric unit used to measure atmospheric pressure.
It's most commonly used in weather forecasting and reporting.
(Technically, one millibar is equal to 0.1 kilopascal, or kPa).
Meteorologists use millibars as the primary unit to measure and report atmospheric pressure.
On weather maps, you'll see lines called isobars, which connect areas of equal pressure, drawn in millibar intervals.
Standard atmospheric pressure at sea level is about 1013 mbar.
This number is a key benchmark for weather conditions:
Yes, for all practical purposes, a millibar (mbar) and a hectopascal (hPa) are the same.
The two units are used interchangeably.
The conversion is simple: 1 mbar = 1 hPa.
While you'll still see millibars in public weather reports (especially in the U.S.), the hectopascal is the preferred SI (International System of Units) unit for global scientific consistency.
A barometer measures barometric pressure—the weight of the air above you—using millibars.
Watching the change in this reading is key to predicting the weather:
A millimeter of mercury (mmHg) is a manometric unit of pressure.
It was historically defined as the pressure generated by a column of mercury exactly one millimeter high.
Today, it is most famous as the unit used in medicine for measuring blood pressure. It is also commonly used in meteorology, aviation, and physics to measure atmospheric pressure or vacuum pressure.
The mmHg unit originates from the invention of the barometer by Evangelista Torricelli in 1643.
Torricelli's device measured atmospheric pressure by seeing how high it could support a column of mercury in a tube.
Standard atmospheric pressure was found to support a column approximately 760 mm high, which established 760 mmHg as a standard reference point.
The most well-known application of mmHg is in medicine.
Blood Pressure: Readings are given as two numbers: systolic pressure (when the heart beats) over diastolic pressure (when the heart rests), such as 120/80 mmHg. This is a critical vital sign for human health.
Meteorology: Used for reporting barometric (atmospheric) pressure, which helps in weather forecasting.
Physics & Engineering: Used for measuring vacuum pressures and other low-pressure systems where precision is needed.
While mmHg is common, other pressure units are standard in different fields. Here are the most common conversions:
Here are some quick reference conversions from millibar (mbar) to millimeter of mercury (mmHg):
| millibar | millimeters of mercury |
|---|---|
| 0.000001 mbar | 7.500637554192106329× 10-7 mmHg |
| 0.001 mbar | 0.0007500637554192106329 mmHg |
| 0.1 mbar | 0.07500637554192106329 mmHg |
| 1 mbar | 0.7500637554192106329 mmHg |
| 2 mbar | 1.5001275108384212658 mmHg |
| 3 mbar | 2.2501912662576318987 mmHg |
| 4 mbar | 3.0002550216768425316 mmHg |
| 5 mbar | 3.7503187770960531645 mmHg |
| 6 mbar | 4.5003825325152637974 mmHg |
| 7 mbar | 5.2504462879344744303 mmHg |
| 8 mbar | 6.0005100433536850632 mmHg |
| 9 mbar | 6.7505737987728956961 mmHg |
| 10 mbar | 7.500637554192106329 mmHg |
| 20 mbar | 15.001275108384212658 mmHg |
| 30 mbar | 22.501912662576318987 mmHg |
| 40 mbar | 30.002550216768425316 mmHg |
| 50 mbar | 37.503187770960531645 mmHg |
| 100 mbar | 75.00637554192106329 mmHg |
| 1000 mbar | 750.0637554192106329 mmHg |
| 10000 mbar | 7500.637554192106329 mmHg |
Engineering datasheets across Europe write millibar to millimeter of mercury several different ways. The calculation is the same in every one of them.
| Language | Written as | Unit names |
|---|---|---|
| French | mbar en mmHg | millibar → millimètre de mercure |
| Spanish | mbar a mmHg | milibar → milímetro de mercurio |
| Dutch | mbar naar mmHg | millibar → millimeter kwikdruk |
| German | mbar in mmHg | Millibar → Millimeter Quecksilbersäule |
| Polish | mbar na mmHg | milibar → milimetr słupa rtęci |
1 mbar = 0.75006 mmHg. The exact value is one divided by 1.33322.
Divide the pressure in millibars by 1.33322, or multiply by 0.75006. For example, 100 mbar = 75.006 mmHg.
Yes, exactly. One millibar and one hectopascal are both 100 pascals. Weather services relabelled millibars as hectopascals in the 1980s without changing a single reading, so a 1013 mbar chart and a 1013 hPa chart show identical pressure.
1013.25 mbar = 760 mmHg. That round 760 is where both the torr and the millimeter of mercury originally came from.
Millibars and hectopascals dominate meteorology and vacuum work, while millimeters of mercury remain standard in medicine and in older laboratory gauges. A vacuum of 50 mbar = 37.503 mmHg reads very differently depending on which convention the gauge uses.
For all Pressure converters, choose units using the From/To dropdowns above.