How to Convert Inches of mercury to Kilopascals (inHg to kPa)
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 kilopascals by hand, with examples and a quick-reference table.
The conversion
To convert inches of mercury to kilopascals, multiply the value by 3.386389. To go the other way, divide by the same number (or multiply by 0.2952998016). For a quick estimate, multiply by about 3.4.
Kilopascals = inches of mercury × 3.386389
Worked examples
- 3 inHg = 10.1592 kPa
- 12.5 inHg = 42.3299 kPa
- 75 inHg = 253.9792 kPa
Inches of mercury to Kilopascals table
| Inches of mercury | Kilopascals |
|---|---|
| 1 inHg | 3.3864 kPa |
| 2 inHg | 6.7728 kPa |
| 5 inHg | 16.9319 kPa |
| 10 inHg | 33.8639 kPa |
| 20 inHg | 67.7278 kPa |
| 25 inHg | 84.6597 kPa |
| 50 inHg | 169.3195 kPa |
| 100 inHg | 338.6389 kPa |
| 250 inHg | 846.5973 kPa |
| 500 inHg | 1,693.19 kPa |
| 1,000 inHg | 3,386.39 kPa |
Common questions
Is inHg to kPa 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 Kilopascals to Inches of mercury 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.
Mixing similar-sounding units
US and imperial gallons, pints and tons are different sizes, and decimal kilobytes differ from binary kibibytes.
Dropping the units
A bare number without a unit is easy to misread later. Always write the unit with the result.
Background
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.
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.
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 any value, use the Inches of mercury to Kilopascals Converter or browse all pressure converters.
Run your own numbers: Inches of mercury to Kilopascals Converter