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Pressure

cmH₂Otombar

Convert centimetres of water column (cmH₂O) to millibars (mbar).

Factor1 cmH₂O = 0.980665 mbar

Converter

cmH₂O

Accepts numbers or expressions, e.g. 150 + 14.7

Result
9.80665mbar

Rendered to 6 significant figures.

Formula

Formula
mbar = cmH₂O × 0.980665

Multiply any value in centimetres of water column by 0.980665 to obtain the value in millibars.

Worked example

Convert 10 cmH₂O to mbar.

  1. 01Start with 10 cmH₂O.
  2. 02Multiply by the conversion factor: 10 × 0.980665 = 9.80665 mbar.
Result10 cmH₂O = 9.80665 mbar

Conversion table

cmH₂Ombar
10.98067
21.9613
54.9033
109.8067
2019.613
5049.033
10098.066
200196.13
500490.33
1000980.66

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from cmH₂O to mbar?
1 cmH₂O equals 0.980665 mbar. To convert, multiply the value in centimetres of water column by 0.980665.
How do I convert 1 cmH₂O to mbar?
1 cmH₂O = 0.980665 mbar. For any value, multiply by 0.980665.
How do I convert mbar back to cmH₂O?
Divide by the same factor — or equivalently, multiply by 1.019716. So 1 mbar = 1.01972 cmH₂O.
When would I need to convert centimetre of water column to millibar?
Pressure conversions between cmH₂O and mbar are common when working with mixed-vendor instrumentation, when piping codes use different units to process datasheets, or when converting field readings into SI for hydraulic calculations.
Is the conversion exact?
The factor shown is precise to at least 7 significant figures. For most process-engineering work this is far better than instrument accuracy. For metrology or trade applications, refer to the relevant national standard (NIST, BIPM, ISO 80000).

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