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Pressure

cmH₂OtoinHg

Convert centimetres of water column (cmH₂O) to inches of mercury (0 °C) (inHg).

Factor1 cmH₂O = 0.02895902 inHg

Converter

cmH₂O

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

Result
2.8959inHg

Rendered to 6 significant figures.

Formula

Formula
inHg = cmH₂O × 0.02895902

Multiply any value in centimetres of water column by 0.02895902 to obtain the value in inches of mercury (0 °C).

Worked example

Convert 100 cmH₂O to inHg.

  1. 01Start with 100 cmH₂O.
  2. 02Multiply by the conversion factor: 100 × 0.02895902 = 2.8959 inHg.
Result100 cmH₂O = 2.8959 inHg

Conversion table

cmH₂OinHg
10.028959
20.057918
50.1448
100.28959
200.57918
501.448
1002.8959
2005.7918
50014.48
100028.959

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from cmH₂O to inHg?
1 cmH₂O equals 0.02895902 inHg. To convert, multiply the value in centimetres of water column by 0.02895902.
How do I convert 1 cmH₂O to inHg?
1 cmH₂O = 0.028959 inHg. For any value, multiply by 0.02895902.
How do I convert inHg back to cmH₂O?
Divide by the same factor — or equivalently, multiply by 34.53156. So 1 inHg = 34.5316 cmH₂O.
When would I need to convert centimetre of water column to inch of mercury (0 °C)?
Pressure conversions between cmH₂O and inHg 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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