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Kilopascal to Millimeter of Water Column Converter

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

Quick Answer

1 Kilopascal = 101.971621 millimeters of water column

Formula: Kilopascal × conversion factor = Millimeter of Water Column

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

Kilopascal to Millimeter of Water Column Calculator

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

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

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

Formula:

mmH₂O = kPa × 101.972

Example Calculation:

1 kPa = 101.971621 mmH₂O

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 Kilopascal and a Millimeter of Water Column?

1 kPa = 1,000 Pa = 0.145038 PSI = 0.01 bar = 10 hPa = 10 mbar = 0.00987 atm = 7.5 mmHg

Why Kilopascal?

The kilopascal is the practical SI unit for everyday pressures:

  • Pascal is too small: 1 Pa = fingernail scratch pressure (not useful)
  • Megapascal is too large: 1 MPa = industrial level (uncommon for most uses)
  • Kilopascal is "just right": 100-300 kPa range covers most everyday pressures
  • SI standard: International standard for tire pressure, medical, engineering
  • Clean conversions: Exactly 0.145 PSI, exactly 0.01 bar

1 mmH₂O = 9.807 Pa = 0.09807 mbar = 0.001422 PSI = 0.0736 mmHg = 0.03937 inH₂O

Key relationships:

  • 25.4 mmH₂O = 1 inH₂O
  • 13.6 mmH₂O ≈ 1 mmHg
  • 102 mmH₂O ≈ 1 kPa

Physical meaning: Pressure exerted by 1-millimeter column of water at 4°C

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

Common Uses and Applications: kilopascals vs millimeters of water column

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

Common Uses for kilopascals

Automotive: Tire pressure (international standard, except USA).

  • Car manufacturers specify tire pressure in kPa on door jamb
  • Repair manuals use kPa
  • Tire pressure gauges often have kPa scale

Medical: Blood pressure equipment (replacing mmHg in some regions).

  • Modern digital blood pressure monitors often display kPa
  • Medical research uses kPa
  • Gradual transition from mmHg (some regions still use mmHg)

Meteorology: Atmospheric pressure (101.325 kPa at sea level).

  • European weather reports sometimes use kPa
  • Upper atmosphere measurements in kPa
  • Pressure profiling in meteorology

Engineering: Structural loads, material strength, HVAC systems.

  • Material testing: tensile strength in MPa, stress in kPa
  • Building code pressure ratings in kPa
  • Water system specifications in kPa

When to Use millimeters of water column

Medical Ventilation: Mechanical ventilators, respiratory therapy. CPAP/BiPAP: Sleep apnea treatment pressure settings. Precision Instruments: Low differential pressure measurements. European HVAC: Clean room pressurization (metric countries).

Additional Unit Information

About Kilopascal (kPa)

How do I convert kPa to PSI?

Formula: PSI = kPa × 0.145038 (or kPa ÷ 6.895)

Examples:

  • 100 kPa = 14.5 PSI
  • 200 kPa = 29 PSI (bicycle tire)
  • 220 kPa = 32 PSI (typical car tire)
  • 240 kPa = 35 PSI (SUV tire)
  • 600 kPa = 87 PSI (road bike)

kPa to PSI converter →

What is 32 PSI in kPa?

32 PSI = 220.6 kPa (standard car tire pressure)

Common tire pressures:

  • 30 PSI = 207 kPa
  • 32 PSI = 221 kPa (most common)
  • 35 PSI = 241 kPa (SUVs, loaded vehicles)
  • 40 PSI = 276 kPa (trucks, some SUVs)

PSI to kPa converter →

How many kPa in 1 bar?

1 bar = 100 kPa exactly

Examples:

  • 0.5 bar = 50 kPa
  • 1 bar = 100 kPa
  • 2 bar = 200 kPa (bicycle tire)
  • 2.5 bar = 250 kPa (car tire)
  • 10 bar = 1,000 kPa = 1 MPa

Bar to kPa converter →

Why do some countries use kPa and others PSI for tires?

kPa (kilopascal): International standard (SI unit)

  • Used in: Europe, Asia, Australia, Canada, most of world
  • Metric system, easier calculations
  • Appears on all tire sidewalls globally

PSI (pounds per square inch): US customary unit

  • Used in: United States primarily
  • Imperial system, traditional in US
  • Also appears on tire sidewalls

Dual labeling: Modern tires show both (e.g., "32 PSI / 220 kPa")

Conversion tip: Multiply kPa by 0.145 to get PSI, or divide PSI by 6.895 to get kPa

Is kPa replacing mmHg for blood pressure?

Transitioning, but slow:

mmHg still dominant: Most medical equipment, patient communication uses mmHg kPa in some regions: SI-compliant medical devices show kPa Dual display: Many modern BP monitors show both

Why slow transition?:

  • Historical familiarity (120/80 mmHg)
  • Medical education based on mmHg
  • Patient understanding
  • International guidelines still use mmHg

Conversion: 1 kPa ≈ 7.5 mmHg, so 120/80 mmHg = 16/10.7 kPa (less intuitive)

About Millimeter of Water Column (mmH₂O)

How do I convert mmH₂O to cmH₂O?

Simple: Divide by 10

1 cmH₂O = 10 mmH₂O

Examples (medical ventilators often use cmH₂O):

  • 100 mmH₂O = 10 cmH₂O (PEEP setting)
  • 200 mmH₂O = 20 cmH₂O (peak pressure)
  • 50 mmH₂O = 5 cmH₂O (CPAP setting)
  • 150 mmH₂O = 15 cmH₂O (typical ventilator)

Medical context: "PEEP of 5" means 5 cmH₂O = 50 mmH₂O

How do I convert mmH₂O to Pascals or mbar?

Formula:

  • Pa = mmH₂O × 9.807
  • mbar = mmH₂O × 0.09807

Examples:

  • 100 mmH₂O = 981 Pa ≈ 9.8 mbar (CPAP)
  • 200 mmH₂O = 1,961 Pa ≈ 19.6 mbar (ventilator)
  • 50 mmH₂O = 490 Pa ≈ 4.9 mbar (low PEEP)
  • 10 mmH₂O = 98 Pa ≈ 1 mbar (clean room)

Quick approximation: 100 mmH₂O ≈ 1 kPa

mmH₂O to Pascal converter →

What is normal CPAP pressure in mmH₂O?

Typical CPAP range: 40-140 mmH₂O (4-14 cmH₂O)

By severity:

  • Mild sleep apnea: 40-60 mmH₂O (4-6 cmH₂O)
  • Moderate sleep apnea: 60-100 mmH₂O (6-10 cmH₂O)
  • Severe sleep apnea: 100-140 mmH₂O (10-14 cmH₂O)

Starting pressure: Usually 40 mmH₂O (4 cmH₂O), titrated upward

Maximum typical: 200 mmH₂O (20 cmH₂O) for severe cases

Note: CPAP machines usually display in cmH₂O, not mmH₂O

  • Setting of "8" = 8 cmH₂O = 80 mmH₂O

What is PEEP in ventilators?

PEEP = Positive End-Expiratory Pressure

Pressure maintained in lungs at end of exhalation (prevents alveolar collapse)

Normal PEEP: 50 mmH₂O (5 cmH₂O) Moderate PEEP: 50-100 mmH₂O (5-10 cmH₂O) High PEEP: 100-200 mmH₂O (10-20 cmH₂O)

Used for:

  • Oxygenation improvement
  • Preventing lung collapse
  • ARDS (Acute Respiratory Distress Syndrome)
  • Pulmonary edema

Too high: Can cause lung damage (barotrauma) Too low: Alveoli collapse, poor oxygenation

Example ventilator settings:

  • Peak pressure: 200 mmH₂O (20 cmH₂O)
  • PEEP: 50 mmH₂O (5 cmH₂O)
  • Tidal volume: 500 mL

Why use mmH₂O instead of kPa or mmHg?

Medical respiratory context:

mmH₂O preferred:

  • Appropriate scale: Ventilator pressures 50-300 mmH₂O (vs 0.5-3 kPa - awkward decimals)
  • Historical: Water manometers originally used
  • Precision: 1 mmH₂O resolution appropriate for therapy adjustments
  • International standard: ISO, medical device standards use cmH₂O/mmH₂O
  • Clinical familiarity: Respiratory therapists trained in cmH₂O

Not mmHg because:

  • mmHg too large (1 mmHg = 13.6 mmH₂O)
  • mmHg used for blood pressure, not airway pressure
  • Less precise for ventilator adjustments

Not kPa because:

  • Requires decimal precision (8 cmH₂O = 0.78 kPa)
  • Less intuitive for clinicians
  • Though some modern ventilators offer kPa display option

Conversion: 100 mmH₂O = 10 cmH₂O = 0.98 kPa = 7.4 mmHg

Conversion Table: Kilopascal to Millimeter of Water Column

Kilopascal (kPa)Millimeter of Water Column (mmH₂O)
0.550.986
1101.972
1.5152.957
2203.943
5509.858
101,019.716
252,549.291
505,098.581
10010,197.162
25025,492.905
50050,985.811
1,000101,971.621

People Also Ask

How do I convert Kilopascal to Millimeter of Water Column?

To convert Kilopascal to Millimeter of Water Column, enter the value in Kilopascal 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 Kilopascal to Millimeter of Water Column?

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

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

Learn more →

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

Kilopascal and Millimeter of Water Column 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 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 TorrTechnical Atmosphere to Millimeter of Mercury

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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