How do you convert inches of mercury to hectopascals?

To convert inches of mercury (inHg) to hectopascals (hPa), multiply the pressure in inches of mercury by 33.86389 (hectopascals = inches of mercury × 33.86389).

What is 29.92 inches of mercury in hectopascals?

29.92 inches of mercury (29.92 inHg) is equal to 1,013.20759 hectopascals (1,013.20759 hPa).

Which is larger, 1 inch of mercury (inhg) (inHg) or 1 hectopascal (hPa)?

One inch of mercury (inhg) (inHg) is larger than one hectopascal (hPa). Specifically, 1 inHg contains 33.86389 hPa, whereas 1 hPa is 0.02953 inHg.

How do I convert back from hectopascals (hPa) to inches of mercury (inHg)?

To reverse the calculation from hPa to inHg, multiply your hectopascal value by the inverse factor 0.02953 (or divide by 33.86389). 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 hPa results to?

For everyday comparisons and quick estimates, rounding to 2 decimal places is usually sufficient (for example, 29.92 inHg ≈ 1,013.21 hPa). For engineering, laboratory, or machining specifications, select 4 or 6 decimals—or Scientific (10ⁿ) mode—in the calculator toolbar above.

Inches of Mercury to Hectopascals Converter

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

Hectopascals to Inches of Mercury (hPa → inHg)

Convert Inches of Mercury to Hectopascals

Enter a value in inches of mercury (inHg) to convert to hectopascals (hPa).

Value (inHg)

From

Result

•

1,013.2075888hectopascals

29.92 inHg = 1,013.2075888 hPa

Result updates automatically

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Equivalent Measurements Across UnitsFor 29.92 inHg

Pascals101,320.75888 Pa

Kilopascals101.32076 kPa

Bars1.01321 bar

PSI14.69533 psi

Atmospheres0.99996 atm

Suggested Conversions

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

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Inch of Mercury to Hectopascal Conversion Table

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

Inches of Mercury (inHg)	Hectopascals (hPa)
1 inHg	33.86389 hPa
2 inHg	67.72778 hPa
5 inHg	169.31945 hPa
10 inHg	338.6389 hPa
14.96 inHg	506.6037944 hPa
15 inHg	507.95835 hPa
20 inHg	677.2778 hPa
25 inHg	846.59725 hPa
29.92 inHg	1,013.2075888 hPa
30 inHg	1,015.9167 hPa

How to Convert Inches of Mercury to Hectopascals

To convert inches of mercury to hectopascals, multiply the pressure by the following conversion ratio: 33.86389 hectopascals/inch of mercury.

Since one inch of mercury is equal to 33.86389 hectopascals, you can use this simple formula to convert:

hectopascals = inches of mercury × 33.86389

The pressure in hectopascals is equal to the pressure in inches of mercury multiplied by 33.86389.

For example, here's how to convert 29.92 inches of mercury to hectopascals using the formula above.

hectopascals = (29.92 inHg × 33.86389) = 1,013.2075888 hPa

How Many Hectopascals Are in an Inch of Mercury?

There are 33.86389 hectopascals in an inch of mercury, which is why we use this value in the formula above.

1 inHg = 33.86389 hPa|1 hPa = 0.02953 inHg

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

Inches of Mercury and hectopascals 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 Hectopascal?

A hectopascal is a unit of pressure equal to 100 pascals (Pa), the base unit for pressure. Equal to 100 Pascals (identical to 1 millibar). [2]

The hectopascal is classified as a metric and SI-compatible unit of pressure. Hectopascals can be abbreviated as hPa; for example, 1 hectopascal can be written as 1 hPa.

In the metric system, "hecto" is the standard SI prefix for hundreds, or 10². This makes the hectopascal (hPa) a convenient decimal multiple of the pascal (Pa).

In practice, hectopascals (hPa) are widely used across standard pressure applications within SI metric workflows, engineering documentation, and technical data sheets.

Learn more about hectopascals in our Pressure Converter.

When converting pressure between inches of mercury (inHg) and hectopascals (hPa), keep full floating-point precision (1 inHg = 33.86389 hPa; 1 hPa = 0.02953 inHg) during intermediate calculations and round only the final hectopascal figure to match your instrument tolerance.

More Inch of Mercury & Hectopascal Conversions

Need to calculate in the opposite direction? Use our hectopascals to inches of mercury converter (hPa to inHg) to switch your starting unit immediately. You can also explore related tools such as converting pascals to hectopascals, converting psi to bars, or converting bars to psi.

Convert from Inches of Mercury

Convert to Hectopascals

Frequently Asked Questions

There are 33.86389 hectopascals (hPa) in 1 inch of mercury (inHg). Conversely, 1 hectopascal (hPa) is equal to 0.02953 inches of mercury (inHg).

Pressure Converter

Quick Info

Direct Factor: 1 inch of mercury (inhg) (inHg) equals 33.86389 hectopascals (hPa).
Inverse Factor: 1 hectopascal (hPa) equals 0.02953 inches of mercury (inHg).
Formula: hectopascals = inches of mercury × 33.86389.
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.

Hectopascal (hPa)

Equal to 100 Pascals (identical to 1 millibar).

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 Hectopascals (hPa)
NIST SP 811 Standard
[2]
NIST CUU (Derived SI Unit: Pascal (Pa))·Unit Specifications: Inch of Mercury (inHg) (inHg) & Hectopascal (hPa)
NIST CUU Specification
[3]
BIPM (SI Brochure (9th Ed.) — Mechanics)·Conversion Factors & Mathematical Basis (inHg to hPa)
BIPM Reference

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