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Millimeter of Water Column to Bar Converter

Convert millimeters of water column to bars with our free online pressure converter.

Quick Answer

1 Millimeter of Water Column = 0.0000981 bars

Formula: Millimeter of Water Column × conversion factor = Bar

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: November 2025Reviewed by: Sam Mathew, Software Engineer

Millimeter of Water Column to Bar Calculator

How to Use the Millimeter of Water Column to Bar Calculator:

  1. Enter the value you want to convert in the 'From' field (Millimeter of Water Column).
  2. The converted value in Bar 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 Millimeter of Water Column to Bar: Step-by-Step Guide

Converting Millimeter of Water Column to Bar involves multiplying the value by a specific conversion factor, as shown in the formula below.

Formula:

bar = mmH₂O × 0.0000980665

Example Calculation:

1 mmH₂O = 0.0000981 bar

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 Millimeter of Water Column and a Bar?

The bar is a metric unit of pressure defined as exactly 100,000 pascals (100 kPa). One bar is approximately equal to atmospheric pressure at sea level. 1 bar = 100,000 Pa = 100 kPa = 14.5038 PSI = 0.986923 atm.

Note: The Millimeter of Water Column is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Bar belongs to the imperial/US customary system.

History of the Millimeter of Water Column and Bar

Introduced in 1909 by British meteorologist William Napier Shaw. Named after "barometer". Recognized by CIPM in 1982 as acceptable for use with SI units due to widespread adoption in industry and meteorology.

Common Uses and Applications: millimeters of water column vs bars

Explore the typical applications for both Millimeter of Water Column (imperial/US) and Bar (imperial/US) to understand their common contexts.

Common Uses for millimeters of water column

When to Use bars

European Automotive: Universal tire pressure unit in Europe. Car tires typically 2.0-2.5 bar. Industrial: Standard for hydraulics, compressed air, and pneumatics. Meteorology: Used alongside millibar (mbar) for weather reporting. Diving: Scuba tank pressures (200-300 bar).

Additional Unit Information

About Bar (bar)

How do I convert bar to PSI?

Formula: PSI = bar × 14.5. Example: 2 bar = 29 PSI, 2.5 bar = 36.3 PSI. Bar to PSI converter →

What is 2.5 bar in PSI?

2.5 bar = 36.3 PSI. This is typical for SUVs, vans, and high-performance cars.

How many bar is atmospheric pressure?

1.01325 bar exactly at sea level. Often rounded to 1 bar for practical calculations.

Conversion Table: Millimeter of Water Column to Bar

Millimeter of Water Column (mmH₂O)Bar (bar)
0.50
10
1.50
20
50.001
100.001
250.003
500.005
1000.01
2500.025
5000.049
1,0000.098

People Also Ask

How do I convert Millimeter of Water Column to Bar?

To convert Millimeter of Water Column to Bar, enter the value in Millimeter of Water Column 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.

Learn more →

What is the conversion factor from Millimeter of Water Column to Bar?

The conversion factor depends on the specific relationship between Millimeter of Water Column and Bar. 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 Bar back to Millimeter of Water Column?

Yes! You can easily convert Bar back to Millimeter of Water Column by using the swap button (⇌) in the calculator above, or by visiting our Bar to Millimeter of Water Column converter page. You can also explore other pressure conversions on our category page.

Learn more →

What are common uses for Millimeter of Water Column and Bar?

Millimeter of Water Column and Bar 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.

Helpful 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: November 14, 2025