Inches of Mercury to Millipascals Converter
Enter the pressure in inches of mercury below to convert it to millipascals.
Convert Inches of Mercury to Millipascals
Enter a value in inches of mercury (inHg) to convert to millipascals (mPa).
Inch of Mercury to Millipascal Conversion Table
Table showing various inch of mercury measurements converted to millipascals. Click any preset value or arrow to load it into the converter.
| Inches of Mercury (inHg) | Millipascals (mPa) |
|---|---|
| 0.0000001 inHg | 0.3386389 mPa |
| 0.0000002 inHg | 0.6772778 mPa |
| 0.0000003 inHg | 1.0159167 mPa |
| 0.0000004 inHg | 1.3545556 mPa |
| 0.0000005 inHg | 1.6931945 mPa |
| 0.0000006 inHg | 2.0318334 mPa |
| 0.0000007 inHg | 2.3704723 mPa |
| 0.0000008 inHg | 2.7091112 mPa |
| 0.0000009 inHg | 3.0477501 mPa |
| 0.00000001 inHg | 0.0338639 mPa |
How to Convert Inches of Mercury to Millipascals
To convert inches of mercury to millipascals, multiply the pressure by the following conversion ratio: 3,386,389 millipascals/inch of mercury.
Since one inch of mercury is equal to 3,386,389 millipascals, you can use this simple formula to convert:
The pressure in millipascals is equal to the pressure in inches of mercury multiplied by 3,386,389.
For example, here's how to convert 5 inches of mercury to millipascals using the formula above.
How Many Millipascals Are in an Inch of Mercury?
There are 3,386,389 millipascals in an inch of mercury, which is why we use this value in the formula above.
Our inch of mercury to millipascal calculator automatically converts your pressure measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.
Inches of Mercury and millipascals are both units used to measure pressure. Keep reading to learn more about each unit.
What Is an Inch of Mercury?
An inch of mercury is a unit of pressure equal to 3,386.389 pascals (Pa), the base unit for pressure. Aviation altimeter & weather barometer unit equal to 3,386.389 Pascals. [1]
The inch of mercury is classified as a US customary unit of pressure. Inches of Mercury can be abbreviated as inHg; for example, 1 inch of mercury can be written as 1 inHg.
When working with inches of mercury (inHg) in formulas or technical specifications, always verify whether your target system uses SI metric, US customary, or British imperial standards.
In practice, inches of mercury (inHg) are widely used across large-scale industrial, bulk, and macro-level pressure specifications within US customary workflows, engineering documentation, and technical data sheets.
What Is a Millipascal?
A millipascal is a unit of pressure equal to 1/1,000 of a pascal (0.001 Pa). One-thousandth of a Pascal. [2]
The millipascal is classified as a metric and SI-compatible unit of pressure. Millipascals can be abbreviated as mPa; for example, 1 millipascal can be written as 1 mPa.
In the metric system, "milli" is the standard SI prefix for thousandths, or 10⁻³. This makes the millipascal (mPa) a convenient decimal multiple of the pascal (Pa).
In practice, millipascals (mPa) are widely used across fine-tolerance laboratory, analytical, and micro-scale pressure measurements within SI metric workflows, engineering documentation, and technical data sheets.
When converting pressure between inches of mercury (inHg) and millipascals (mPa), keep full floating-point precision (1 inHg = 3,386,389 mPa; 1 mPa = 0.000000295 inHg) during intermediate calculations and round only the final millipascal figure to match your instrument tolerance.
More Inch of Mercury & Millipascal Conversions
Need to calculate in the opposite direction? Use our millipascals to inches of mercury calculator to switch your starting unit immediately. You can also explore related tools such as converting millipascals to inches of mercury, converting inches of mercury to hectopascals, or converting psi to bars.
Convert from Inches of Mercury
Frequently Asked Questions
References
- [1]NIST SP 811 StandardNIST SP 811 (NIST SP 811 App. B.9 (Pressure & Stress))·Pressure Metrology Standard — Inches of Mercury (inHg) to Millipascals (mPa)
- [2]NIST CUU SpecificationNIST CUU (Derived SI Unit: Pascal (Pa))·Unit Specifications: Inch of Mercury (inHg) (inHg) & Millipascal (mPa)
- [3]BIPM ReferenceBIPM (SI Brochure (9th Ed.) — Mechanics)·Conversion Factors & Mathematical Basis (inHg to mPa)