This converter turns millimeters of mercury into millibars instantly, using the exact factor 1 millimeter of mercury = 1.333223874 millibars. Type any number and the result updates as you go — nothing is sent to a server, so the arithmetic happens entirely in your browser.
The clinical unit for blood pressure worldwide. The meteorologist’s unit — sea-level pressure averages 1013.25 mbar.
Because the relationship is a simple proportion, one multiplication does the whole job. The table further down gives pre-computed values for the amounts people look up most often, and the result panel also reports the reverse conversion so you can check the figure both ways.
The formula
millimeters of mercury- The amount you are converting, measured in millimeters of mercury
1.333223874- The exact number of millibars in one millimeter of mercury
millibars- The converted result
How it works, step by step
- Enter the number of millimeters of mercury you want to convert.
- The value is multiplied by 1.333223874, the exact conversion factor.
- The result is displayed in millibars, rounded for readability.
- The unrounded value and the reverse conversion appear underneath so you can verify it.
Worked examples
Converting 5 millimeters of mercury
Multiply 5 by 1.3332239. That gives 6.6661 millibars. A quick sanity check: one millimeter of mercury is larger than one millibar, so the number should get bigger — and it does.
Converting 72 millimeters of mercury
72 × 1.3332239 = 95.9921 millibars. Working backwards, 95.9921 ÷ 1.3332239 returns 72 millimeters of mercury, which confirms the factor is applied the right way round.
How to read your score
Frequently asked questions
How many millibars are in one millimeter of mercury?
Exactly 1.333223874. Every conversion on this page is that single number multiplied by your input, so the result carries no rounding error beyond what is shown.
What is the formula to convert millimeters of mercury to millibars?
Millibars = millimeters of mercury × 1.333223874. To reverse it, divide instead: millimeters of mercury = millibars ÷ 1.333223874, which is the same as multiplying by 0.7500615758.
Is the millimeter of mercury bigger than the millibar?
Yes. One millimeter of mercury equals 1.33322 millibars, so it is the larger unit.
Why does my answer differ slightly from other mmhg to millibar converters?
Most differences come from rounding the factor too early. This tool keeps full double precision through the calculation and only rounds at the final display step, and it also shows the unrounded value so you can see exactly where any difference appears.
What is a millimeter of mercury?
The clinical unit for blood pressure worldwide.
What is a millibar?
The meteorologist’s unit — sea-level pressure averages 1013.25 mbar.
Millimeters Of Mercury to millibars reference table
| Millimeters Of Mercury | Millibars |
|---|---|
| 0.5 mmHg | 0.666612 mbar |
| 1 mmHg | 1.3332 mbar |
| 2 mmHg | 2.6664 mbar |
| 3 mmHg | 3.9997 mbar |
| 5 mmHg | 6.6661 mbar |
| 10 mmHg | 13.3322 mbar |
| 15 mmHg | 19.9984 mbar |
| 20 mmHg | 26.6645 mbar |
| 25 mmHg | 33.3306 mbar |
| 50 mmHg | 66.6612 mbar |
| 75 mmHg | 99.9918 mbar |
| 100 mmHg | 133.3224 mbar |
| 250 mmHg | 333.306 mbar |
| 500 mmHg | 666.6119 mbar |
| 1000 mmHg | 1,333.22 mbar |
Exact factor: 1 millimeter of mercury = 1.333223874 millibars. Values rounded for display.