How do you convert hectopascals to inches of mercury?

To convert hectopascals (hPa) to inches of mercury (inHg), multiply the pressure in hectopascals by 0.02953 (inches of mercury = hectopascals × 0.02953).

What is 1013.25 hectopascals in inches of mercury?

1013.25 hectopascals (1013.25 hPa) is equal to 29.92125 inches of mercury (29.92125 inHg).

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

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

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

To reverse the calculation from inHg to hPa, multiply your inch of mercury (inhg) value by the inverse factor 33.86389 (or divide by 0.02953). You can also click the Swap button in the tool above to flip directions in one click.

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

For everyday comparisons and quick estimates, rounding to 2 decimal places is usually sufficient (for example, 1013.25 hPa ≈ 29.92 inHg). For engineering, laboratory, or machining specifications, select 4 or 6 decimals—or Scientific (10ⁿ) mode—in the calculator toolbar above.

Hectopascals to Inches of Mercury Converter

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

Inches of Mercury to Hectopascals (inHg → hPa)

Convert Hectopascals to Inches of Mercury

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

Value (hPa)

From

Result

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29.921252402inches of mercury

1013.25 hPa = 29.921252402 inHg

Result updates automatically

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Equivalent Measurements Across UnitsFor 1013.25 hPa

Pascals101,325 Pa

Kilopascals101.325 kPa

Bars1.01325 bar

PSI14.69595 psi

Atmospheres1 atm

Suggested Conversions

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

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Hectopascal to Inch of Mercury Conversion Table

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

Hectopascals (hPa)	Inches of Mercury (inHg)
1 hPa	0.02953 inHg
2 hPa	0.05906 inHg
5 hPa	0.1476499 inHg
10 hPa	0.2952998 inHg
15 hPa	0.4429497 inHg
20 hPa	0.5905996 inHg
25 hPa	0.7382495 inHg
30 hPa	0.8858994 inHg
50 hPa	1.476499 inHg
75 hPa	2.2147485 inHg

How to Convert Hectopascals to Inches of Mercury

To convert hectopascals to inches of mercury, multiply the pressure by the following conversion ratio: 0.02953 inches of mercury/hectopascal.

Since one hectopascal is equal to 0.02953 inches of mercury, you can use this simple formula to convert:

inches of mercury = hectopascals × 0.02953

The pressure in inches of mercury is equal to the pressure in hectopascals multiplied by 0.02953.

For example, here's how to convert 1013.25 hectopascals to inches of mercury using the formula above.

inches of mercury = (1013.25 hPa × 0.02953) = 29.9212524 inHg

How Many Inches of Mercury Are in a Hectopascal?

There are 0.02953 inches of mercury in a hectopascal, which is why we use this value in the formula above.

1 hPa = 0.02953 inHg|1 inHg = 33.86389 hPa

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

Hectopascals and inches of mercury are both units used to measure pressure. Keep reading to learn more about each unit.

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). [1]

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.

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. [2]

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.

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

More Hectopascal & Inch of Mercury Conversions

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

Convert from Hectopascals

Convert to Inches of Mercury

Frequently Asked Questions

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

Pressure Converter

Quick Info

Direct Factor: 1 hectopascal (hPa) equals 0.02953 inches of mercury (inHg).
Inverse Factor: 1 inch of mercury (inhg) (inHg) equals 33.86389 hectopascals (hPa).
Formula: inches of mercury = hectopascals × 0.02953.
Verified Precision: Anchored to official NIST SP 811 and ISO/IEC 80000 standards.

Units Comparison

Hectopascal (hPa)

Equal to 100 Pascals (identical to 1 millibar).

Inch of Mercury (inHg) (inHg)

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

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

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