How do you convert inches of mercury to megapascals?

To convert inches of mercury (inHg) to megapascals (MPa), multiply the pressure in inches of mercury by 0.00338638 (megapascals = inches of mercury × 0.00338638).

What is 5 inches of mercury in megapascals?

5 inches of mercury (5 inHg) is equal to 0.01693 megapascals (0.01693 MPa).

Which is larger, 1 inch of mercury (inhg) (inHg) or 1 megapascal (MPa)?

One megapascal (MPa) is larger than one inch of mercury (inhg) (inHg). Specifically, 1 MPa equals 295.2998 inHg, while 1 inHg is 0.00338638 MPa.

How do I convert back from megapascals (MPa) to inches of mercury (inHg)?

To reverse the calculation from MPa to inHg, multiply your megapascal value by the inverse factor 295.2998 (or divide by 0.00338638). You can also click the Swap button in the tool above to flip directions in one click.

How many decimal places should I round inHg to MPa results to?

For everyday comparisons and quick estimates, rounding to 2 decimal places is usually sufficient (for example, 5 inHg ≈ 0.02 MPa). For engineering, laboratory, or machining specifications, select 4 or 6 decimals—or Scientific (10ⁿ) mode—in the calculator toolbar above.

Inches of Mercury to Megapascals Converter

Enter the pressure in inches of mercury below to convert it to megapascals.

Megapascals to Inches of Mercury (MPa → inHg)

Convert Inches of Mercury to Megapascals

Enter a value in inches of mercury (inHg) to convert to megapascals (MPa).

Value (inHg)

From

Result

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0.016931945megapascals

5 inHg = 0.016931945 MPa

Result updates automatically

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Equivalent Measurements Across UnitsFor 5 inHg

Pascals16,931.945 Pa

Kilopascals16.93195 kPa

Bars0.16932 bar

PSI2.45577 psi

Atmospheres0.16711 atm

Suggested Conversions

Reference:NIST SP 811 (NIST SP 811 App. B.9 (Pressure & Stress))

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Inch of Mercury to Megapascal Conversion Table

Table showing various inch of mercury measurements converted to megapascals. Click any preset value or arrow to load it into the converter.

Inches of Mercury (inHg)	Megapascals (MPa)
1 inHg	0.0033864 MPa
2 inHg	0.0067728 MPa
2.5 inHg	0.008466 MPa
5 inHg	0.0169319 MPa
10 inHg	0.0338639 MPa
15 inHg	0.0507958 MPa
20 inHg	0.0677278 MPa
25 inHg	0.0846597 MPa
30 inHg	0.1015917 MPa
50 inHg	0.1693195 MPa

How to Convert Inches of Mercury to Megapascals

To convert inches of mercury to megapascals, multiply the pressure by the following conversion ratio: 0.0033864 megapascals/inch of mercury.

Since one inch of mercury is equal to 0.0033864 megapascals, you can use this simple formula to convert:

megapascals = inches of mercury × 0.0033864

The pressure in megapascals is equal to the pressure in inches of mercury multiplied by 0.0033864.

For example, here's how to convert 5 inches of mercury to megapascals using the formula above.

megapascals = (5 inHg × 0.0033864) = 0.0169319 MPa

How Many Megapascals Are in an Inch of Mercury?

There are 0.0033864 megapascals in an inch of mercury, which is why we use this value in the formula above.

1 inHg = 0.0033864 MPa|1 MPa = 295.2998016 inHg

Our inch of mercury to megapascal calculator automatically converts your pressure measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.

Inches of Mercury and megapascals 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.

Learn more about inches of mercury in our Pressure Converter.

What Is a Megapascal?

A megapascal is a unit of pressure equal to 1,000,000 pascals (Pa), the base unit for pressure. Equal to 1,000,000 Pascals (identically 1 N/mm²). [2]

The megapascal is classified as an International System of Units (SI) unit of pressure. Megapascals can be abbreviated as MPa; for example, 1 megapascal can be written as 1 MPa.

In the metric system, "mega" is the standard SI prefix for millions, or 10⁶. This makes the megapascal (MPa) a convenient decimal multiple of the pascal (Pa).

In practice, megapascals (MPa) are widely used across large-scale industrial, bulk, and macro-level pressure specifications within International System of Units (SI) workflows, engineering documentation, and technical data sheets.

Learn more about megapascals in our Pressure Converter.

When converting pressure between inches of mercury (inHg) and megapascals (MPa), keep full floating-point precision (1 inHg = 0.0033864 MPa; 1 MPa = 295.2998016 inHg) during intermediate calculations and round only the final megapascal figure to match your instrument tolerance.

More Inch of Mercury & Megapascal Conversions

Need to calculate in the opposite direction? Use our megapascals to inches of mercury calculator to switch your starting unit immediately. You can also explore related tools such as converting megapascals to inches of mercury, converting psi to megapascals, or converting pascals to megapascals.

Convert from Inches of Mercury

Convert to Megapascals

Frequently Asked Questions

There are 0.00338638 megapascals (MPa) in 1 inch of mercury (inHg). Conversely, 1 megapascal (MPa) is equal to 295.2998 inches of mercury (inHg).

Pressure Converter

Quick Info

Direct Factor: 1 inch of mercury (inhg) (inHg) equals 0.00338638 megapascals (MPa).
Inverse Factor: 1 megapascal (MPa) equals 295.2998 inches of mercury (inHg).
Formula: megapascals = inches of mercury × 0.00338638.
Verified Precision: Anchored to official NIST SP 811 and ISO/IEC 80000 standards.

Units Comparison

Inch of Mercury (inHg) (inHg)

Aviation altimeter & weather barometer unit equal to 3,386.389 Pascals.

Megapascal (MPa)

Equal to 1,000,000 Pascals (identically 1 N/mm²).

Pascal (Pa)

SI derived unit of pressure equal to 1 Newton per square meter (N/m²).

References

[1]NIST SP 811 · NIST SP 811 App. B.9 (Pressure & Stress)
Source
[2]NIST CUU · Derived SI Unit: Pascal (Pa)
Source
[3]BIPM · SI Brochure (9th Ed.) — Mechanics
Source

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References

NIST · BIPM · ISO

[1]
NIST SP 811 (NIST SP 811 App. B.9 (Pressure & Stress))·Pressure Metrology Standard — Inches of Mercury (inHg) to Megapascals (MPa)
NIST SP 811 Standard
[2]
NIST CUU (Derived SI Unit: Pascal (Pa))·Unit Specifications: Inch of Mercury (inHg) (inHg) & Megapascal (MPa)
NIST CUU Specification
[3]
BIPM (SI Brochure (9th Ed.) — Mechanics)·Conversion Factors & Mathematical Basis (inHg to MPa)
BIPM Reference

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