How to Convert Inches of mercury to Millibars (inHg to mbar)
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 inches of mercury into millibars by hand, with examples and a quick-reference table.
The conversion
To convert inches of mercury to millibars, multiply the value by 33.86389. To go the other way, divide by the same number (or multiply by 0.0295299802). For a quick estimate, multiply by about 34.
Millibars = inches of mercury × 33.86389
Worked examples
- 3 inHg = 101.5917 mbar
- 12.5 inHg = 423.2986 mbar
- 75 inHg = 2,539.79 mbar
Inches of mercury to Millibars table
| Inches of mercury | Millibars |
|---|---|
| 1 inHg | 33.8639 mbar |
| 2 inHg | 67.7278 mbar |
| 5 inHg | 169.3194 mbar |
| 10 inHg | 338.6389 mbar |
| 20 inHg | 677.2778 mbar |
| 25 inHg | 846.5972 mbar |
| 50 inHg | 1,693.19 mbar |
| 100 inHg | 3,386.39 mbar |
| 250 inHg | 8,465.97 mbar |
| 500 inHg | 16,931.94 mbar |
| 1,000 inHg | 33,863.89 mbar |
Common questions
Is inHg to mbar 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 Millibars to Inches of mercury converter.
Mistakes to avoid
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.
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.
Background
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.
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.
Unit conversion is simply multiplication by a fixed ratio. The ratio between two units of the same quantity never changes, so once you know it you can convert any value in either direction.
For any value, use the Inches of mercury to Millibars Converter or browse all pressure converters.
Run your own numbers: Inches of mercury to Millibars Converter