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Inch of Mercury to Kilopound per Square Inch Converter

Convert inches of mercury to kilopounds per square inch with our free online pressure converter.

Quick Answer

1 Inch of Mercury = 0.000491 kilopounds per square inch

Formula: Inch of Mercury × conversion factor = Kilopound per Square Inch

Use the calculator below for instant, accurate conversions.

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All conversion formulas on UnitsConverter.io have been verified against NIST (National Institute of Standards and Technology) guidelines and international SI standards. Our calculations are accurate to 10 decimal places for standard conversions and use arbitrary precision arithmetic for astronomical units.

Last verified: February 2026Reviewed by: Sam Mathew, Software Engineer

Inch of Mercury to Kilopound per Square Inch Calculator

How to Use the Inch of Mercury to Kilopound per Square Inch Calculator:

  1. Enter the value you want to convert in the 'From' field (Inch of Mercury).
  2. The converted value in Kilopound per Square Inch will appear automatically in the 'To' field.
  3. Use the dropdown menus to select different units within the Pressure category.
  4. Click the swap button (⇌) to reverse the conversion direction.
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How to Convert Inch of Mercury to Kilopound per Square Inch: Step-by-Step Guide

Converting Inch of Mercury to Kilopound per Square Inch involves multiplying the value by a specific conversion factor, as shown in the formula below.

Formula:

ksi = inHg × 0.000491154

Example Calculation:

1 inHg = 0.000491 ksi

Disclaimer: For Reference Only

These conversion results are provided for informational purposes only. While we strive for accuracy, we make no guarantees regarding the precision of these results, especially for conversions involving extremely large or small numbers which may be subject to the inherent limitations of standard computer floating-point arithmetic.

Not for professional use. Results should be verified before use in any critical application. View our Terms of Service for more information.

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What is a Inch of Mercury and a Kilopound per Square Inch?

1 inHg = 3,386.39 Pa = 3.386 kPa = 33.86 mbar = 33.86 hPa = 0.491 PSI = 0.0334 bar = 0.0334 atm = 25.4 mmHg

Key relationship: 29.92 inHg = 1 atmosphere (exactly)

Origin: Mercury Column

The unit literally measures how high mercury rises:

  • Historical: Barometers invented in 1600s used mercury column
  • Measurement: Mercury rises/falls with atmospheric pressure
  • 1 inHg: Mercury column exactly 1 inch high
  • 29.92 inHg: Mercury rises 29.92 inches at sea level (1 atm)
  • Why mercury?: Highest density liquid (narrow barometer), visible, stable

1 ksi = 1,000 PSI = 6.895 MPa = 68.95 bar = 6,895 kPa = 47.88 atm

ksi = kilo-pound per square inch = 1,000 pounds-force per square inch

Also written as: KSI, 1000 PSI, 1 KPSI

Note: The Inch of Mercury is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Kilopound per Square Inch belongs to the imperial/US customary system.

Common Uses and Applications: inches of mercury vs kilopounds per square inch

Explore the typical applications for both Inch of Mercury (imperial/US) and Kilopound per Square Inch (imperial/US) to understand their common contexts.

Common Uses for inches of mercury

US Weather: Barometric pressure in weather forecasts, NOAA reports - THE US standard. Aviation: Altimeter settings (US standard, some international - critical for flight safety). HVAC: Vacuum measurements, duct pressure, system diagnostics. Historical meteorology: Traditional US measurement since early 1900s.

When to Use kilopounds per square inch

Structural Steel: Yield strength, tensile strength specifications (AISC standards). Concrete: Compressive strength testing, design specs. Materials Testing: Tensile testing, compression testing. High-Pressure Systems: Hydraulics, pressure vessels, extreme pressures.

Additional Unit Information

About Inch of Mercury (inHg)

How do I convert inHg to PSI?

Formula: PSI = inHg × 0.491154

Examples:

  • 29.92 inHg = 14.7 PSI (sea level)
  • 30 inHg = 14.74 PSI
  • 28 inHg = 13.75 PSI (hurricane)
  • 25 inHg = 12.28 PSI
  • 20 inHg = 9.82 PSI

inHg to PSI converter →

How many inHg is normal atmospheric pressure?

Standard sea level = 29.92 inHg (exactly 1 atmosphere)

Typical weather range: 29.4-30.5 inHg

Pressure variations:

  • High pressure: 30.2-30.5 inHg (fair weather)
  • Normal: 29.8-30.2 inHg
  • Low pressure: 29.4-29.8 inHg (rain likely)
  • Storm: <29.4 inHg

Barometer rising/falling:

  • Rising: Improving weather
  • Steady: Conditions stable
  • Falling: Weather deteriorating

How do I convert inHg to mbar or hPa?

Formula: mbar (or hPa) = inHg × 33.8639

Examples:

  • 29.92 inHg = 1,013.25 mbar = 1,013.25 hPa (standard)
  • 30.0 inHg = 1,016 mbar
  • 29.0 inHg = 982 mbar (low pressure)
  • 28.0 inHg = 948 mbar (hurricane)
  • 31.0 inHg = 1,050 mbar (high pressure)

inHg to mbar converter → inHg to hPa converter →

Why does US use inHg instead of mbar/hPa?

Historical: US adopted imperial/customary units Mercury barometers: Traditionally marked in inches in US Weather tradition: NOAA, Weather Channel use inHg since inception Familiarity: Public knows "normal is about 30 inches" Aviation: US pilots trained with inHg altimeter settings

Rest of world: Uses mbar or hPa (metric standard)

Conversion: 30 inHg ≈ 1,000 mbar (approximately)

Trend: Slow transition—some US reports now show both units

How do I read a mercury barometer in inHg?

How it works: Mercury column rises/falls with atmospheric pressure

Reading:

  • Look at top of mercury meniscus (curved surface)
  • Read scale at eye level to avoid parallax error
  • Scale typically 28-31 inHg range

Interpreting:

  • 30.2-30.5 inHg: High pressure (fair, clear weather)
  • 29.8-30.2 inHg: Normal (stable conditions)
  • 29.4-29.8 inHg: Low pressure (clouds, possible rain)
  • <29.4 inHg: Very low (storm likely)

Trend matters: Falling rapidly = weather worsening; Rising = improving

Adjustment: Correct for altitude (sea level reading)

About Kilopound per Square Inch (ksi)

How do I convert ksi to MPa?

Formula: MPa = ksi × 6.895

Examples:

  • 36 ksi = 248 MPa (A36 steel)
  • 50 ksi = 345 MPa (A992 steel)
  • 60 ksi = 414 MPa (rebar)
  • 100 ksi = 689 MPa (high-strength)
  • 1 ksi = 6.895 MPa

ksi to MPa converter →

What does "36 ksi steel" mean?

36 ksi = yield strength of structural steel

A36 Steel (most common structural):

  • Yield strength: 36,000 PSI = 36 ksi = 248 MPa
  • Tensile strength: 58-80 ksi (ultimate strength before breaking)
  • Applications: Beams, columns, general construction

Yield strength: Stress at which permanent deformation begins Tensile strength: Maximum stress before failure

Common grades:

  • A36: 36 ksi (older standard, still common)
  • A572 Grade 50: 50 ksi (modern standard)
  • A992: 50 ksi yield (I-beams, wide flanges)

How do I convert ksi to PSI?

Formula: PSI = ksi × 1,000

Examples:

  • 1 ksi = 1,000 PSI
  • 36 ksi = 36,000 PSI (A36 steel)
  • 50 ksi = 50,000 PSI (A992 steel)
  • 4 ksi = 4,000 PSI (concrete)
  • 0.1 ksi = 100 PSI

Why use ksi?: Simpler than writing "36,000 PSI"—say "36 ksi" instead

What is typical concrete strength in ksi?

Residential/Light commercial:

  • Sidewalks, patios: 3 ksi (3,000 PSI)
  • Garage floors, driveways: 3.5-4 ksi
  • Foundation slabs: 3-4 ksi

Commercial:

  • Commercial floors: 4-5 ksi
  • Parking structures: 4-5 ksi
  • Warehouse slabs: 5-6 ksi

Structural:

  • Columns, beams: 5-8 ksi
  • High-rise buildings: 8-14 ksi
  • Bridge elements: 4-6 ksi

Special:

  • Precast prestressed: 5-10 ksi
  • Ultra-high performance: 20-30 ksi

Note: Concrete strength measured at 28 days after pouring

Why does US use ksi instead of MPa?

Historical: US construction industry established with imperial units Standards: AISC, ACI, ASTM all specify ksi Training: US engineers educated with ksi Continuity: Existing specs, calculations, tables in ksi Conversion: 1 ksi ≈ 7 MPa (approximate, easy mental math)

Rest of world: Uses MPa (SI standard)

  • 36 ksi = 248 MPa (A36 steel equivalent)
  • 50 ksi = 345 MPa (common grade)

Dual labeling: International projects often show both units

Conversion Table: Inch of Mercury to Kilopound per Square Inch

Inch of Mercury (inHg)Kilopound per Square Inch (ksi)
0.50
10.001
1.50.001
20.001
50.003
100.005
250.012
500.025
1000.049
2500.123
5000.246
1,0000.491

People Also Ask

How do I convert Inch of Mercury to Kilopound per Square Inch?

To convert Inch of Mercury to Kilopound per Square Inch, enter the value in Inch of Mercury in the calculator above. The conversion will happen automatically. Use our free online converter for instant and accurate results. You can also visit our pressure converter page to convert between other units in this category.

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What is the conversion factor from Inch of Mercury to Kilopound per Square Inch?

The conversion factor depends on the specific relationship between Inch of Mercury and Kilopound per Square Inch. You can find the exact conversion formula and factor on this page. Our calculator handles all calculations automatically. See the conversion table above for common values.

Can I convert Kilopound per Square Inch back to Inch of Mercury?

Yes! You can easily convert Kilopound per Square Inch back to Inch of Mercury by using the swap button (⇌) in the calculator above, or by visiting our Kilopound per Square Inch to Inch of Mercury converter page. You can also explore other pressure conversions on our category page.

Learn more →

What are common uses for Inch of Mercury and Kilopound per Square Inch?

Inch of Mercury and Kilopound per Square Inch are both standard units used in pressure measurements. They are commonly used in various applications including engineering, construction, cooking, and scientific research. Browse our pressure converter for more conversion options.

For more pressure conversion questions, visit our FAQ page or explore our conversion guides.

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All Pressure Conversions

Pascal to KilopascalPascal to MegapascalPascal to HectopascalPascal to BarPascal to MillibarPascal to AtmospherePascal to Technical AtmospherePascal to TorrPascal to Millimeter of MercuryPascal to Inch of MercuryPascal to Pound per Square InchPascal to Kilopound per Square InchPascal to Kilogram-force per Square CentimeterPascal to Kilogram-force per Square MeterPascal to Millimeter of Water ColumnPascal to Inch of Water ColumnKilopascal to PascalKilopascal to MegapascalKilopascal to HectopascalKilopascal to BarKilopascal to MillibarKilopascal to AtmosphereKilopascal to Technical AtmosphereKilopascal to TorrKilopascal to Millimeter of MercuryKilopascal to Inch of MercuryKilopascal to Pound per Square InchKilopascal to Kilopound per Square InchKilopascal to Kilogram-force per Square CentimeterKilopascal to Kilogram-force per Square MeterKilopascal to Millimeter of Water ColumnKilopascal to Inch of Water ColumnMegapascal to PascalMegapascal to KilopascalMegapascal to HectopascalMegapascal to BarMegapascal to MillibarMegapascal to AtmosphereMegapascal to Technical AtmosphereMegapascal to TorrMegapascal to Millimeter of MercuryMegapascal to Inch of MercuryMegapascal to Pound per Square InchMegapascal to Kilopound per Square InchMegapascal to Kilogram-force per Square CentimeterMegapascal to Kilogram-force per Square MeterMegapascal to Millimeter of Water ColumnMegapascal to Inch of Water ColumnHectopascal to PascalHectopascal to KilopascalHectopascal to MegapascalHectopascal to BarHectopascal to MillibarHectopascal to AtmosphereHectopascal to Technical AtmosphereHectopascal to TorrHectopascal to Millimeter of MercuryHectopascal to Inch of MercuryHectopascal to Pound per Square InchHectopascal to Kilopound per Square InchHectopascal to Kilogram-force per Square CentimeterHectopascal to Kilogram-force per Square MeterHectopascal to Millimeter of Water ColumnHectopascal to Inch of Water ColumnBar to PascalBar to KilopascalBar to MegapascalBar to HectopascalBar to MillibarBar to AtmosphereBar to Technical AtmosphereBar to TorrBar to Millimeter of MercuryBar to Inch of MercuryBar to Pound per Square InchBar to Kilopound per Square InchBar to Kilogram-force per Square CentimeterBar to Kilogram-force per Square MeterBar to Millimeter of Water ColumnBar to Inch of Water ColumnMillibar to PascalMillibar to KilopascalMillibar to MegapascalMillibar to HectopascalMillibar to BarMillibar to AtmosphereMillibar to Technical AtmosphereMillibar to TorrMillibar to Millimeter of MercuryMillibar to Inch of MercuryMillibar to Pound per Square InchMillibar to Kilopound per Square InchMillibar to Kilogram-force per Square CentimeterMillibar to Kilogram-force per Square MeterMillibar to Millimeter of Water ColumnMillibar to Inch of Water ColumnAtmosphere to PascalAtmosphere to KilopascalAtmosphere to MegapascalAtmosphere to HectopascalAtmosphere to BarAtmosphere to MillibarAtmosphere to Technical AtmosphereAtmosphere to TorrAtmosphere to Millimeter of MercuryAtmosphere to Inch of MercuryAtmosphere to Pound per Square InchAtmosphere to Kilopound per Square InchAtmosphere to Kilogram-force per Square CentimeterAtmosphere to Kilogram-force per Square MeterAtmosphere to Millimeter of Water ColumnAtmosphere to Inch of Water ColumnTechnical Atmosphere to PascalTechnical Atmosphere to KilopascalTechnical Atmosphere to MegapascalTechnical Atmosphere to HectopascalTechnical Atmosphere to BarTechnical Atmosphere to MillibarTechnical Atmosphere to AtmosphereTechnical Atmosphere to Torr

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Verified Against Authority Standards

All conversion formulas have been verified against international standards and authoritative sources to ensure maximum accuracy and reliability.

NIST Reference on Constants, Units and Uncertainty

National Institute of Standards and Technology — Fundamental physical constants and unit conversions

BIPM SI Units

Bureau International des Poids et Mesures — International System of Units (SI) definitions and standards

ISO 80000

International Organization for Standardization — Quantities and units international standards series

Last verified: February 19, 2026