How to Convert Millibars to Millimetres of mercury (mbar to mmHg)
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 millimetres of mercury by hand, with examples and a quick-reference table.
The conversion
To convert millibars to millimetres of mercury, multiply the value by 0.7500637554. To go the other way, divide by the same number (or multiply by 1.33322). For a quick estimate, multiply by about 0.75.
Millimetres of mercury = millibars × 0.7500637554
Worked examples
- 3 mbar = 2.2502 mmHg
- 12.5 mbar = 9.3758 mmHg
- 75 mbar = 56.2548 mmHg
Millibars to Millimetres of mercury table
| Millibars | Millimetres of mercury |
|---|---|
| 1 mbar | 0.750064 mmHg |
| 2 mbar | 1.5001 mmHg |
| 5 mbar | 3.7503 mmHg |
| 10 mbar | 7.5006 mmHg |
| 20 mbar | 15.0013 mmHg |
| 25 mbar | 18.7516 mmHg |
| 50 mbar | 37.5032 mmHg |
| 100 mbar | 75.0064 mmHg |
| 250 mbar | 187.5159 mmHg |
| 500 mbar | 375.0319 mmHg |
| 1,000 mbar | 750.0638 mmHg |
Common questions
Is mbar to mmHg 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 Millimetres of mercury to Millibars converter.
Mistakes to avoid
Forgetting squared and cubed units
Area and volume factors are the length factor squared or cubed, so 1 m² is about 10.76 sq ft, not 3.28.
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.
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.
Background
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.
Singapore adopted the metric system in the 1970s, replacing imperial units and traditional Chinese measures in most official uses. Metric units are now standard in schools, trade and government, but older units survive in property, markets and imported goods.
For any value, use the Millibars to Millimetres of mercury Converter or browse all pressure converters.
Run your own numbers: Millibars to Millimetres of mercury Converter