How to Convert Millimetres of mercury to Bar (mmHg to bar)
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 millimetres of mercury into bar by hand, with examples and a quick-reference table.
The conversion
To convert millimetres of mercury to bar, multiply the value by 0.00133322. To go the other way, divide by the same number (or multiply by 750.0637554192). For a quick estimate, multiply by about 0.0013.
Bar = millimetres of mercury × 0.00133322
Worked examples
- 3 mmHg = 0.004 bar
- 12.5 mmHg = 0.016665 bar
- 75 mmHg = 0.099991 bar
Millimetres of mercury to Bar table
| Millimetres of mercury | Bar |
|---|---|
| 1 mmHg | 0.001333 bar |
| 2 mmHg | 0.002666 bar |
| 5 mmHg | 0.006666 bar |
| 10 mmHg | 0.013332 bar |
| 20 mmHg | 0.026664 bar |
| 25 mmHg | 0.03333 bar |
| 50 mmHg | 0.066661 bar |
| 100 mmHg | 0.133322 bar |
| 250 mmHg | 0.333305 bar |
| 500 mmHg | 0.66661 bar |
| 1,000 mmHg | 1.3332 bar |
Common questions
Is mmHg to bar 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 Bar to Millimetres of mercury converter.
Mistakes to avoid
Dropping the units
A bare number without a unit is easy to misread later. Always write the unit with the result.
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.
Mixing similar-sounding units
US and imperial gallons, pints and tons are different sizes, and decimal kilobytes differ from binary kibibytes.
Background
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.
Many conversion factors are exact by definition. The inch has been defined as exactly 2.54 centimetres since 1959, and the pound as exactly 0.45359237 kilograms, so conversions involving them can be as precise as you need.
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.
For any value, use the Millimetres of mercury to Bar Converter or browse all pressure converters.
Run your own numbers: Millimetres of mercury to Bar Converter