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Pressure

mmHgtomH₂O

Convert millimetres of mercury (mmHg) to metres of water column (mH₂O).

Factor1 mmHg = 0.0135951 mH₂O

Converter

mmHg

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

Result
10.3323mH₂O

Rendered to 6 significant figures.

Formula

Formula
mH₂O = mmHg × 0.0135951

Multiply any value in millimetres of mercury by 0.0135951 to obtain the value in metres of water column.

Worked example

Convert 760 mmHg to mH₂O.

  1. 01Start with 760 mmHg.
  2. 02Multiply by the conversion factor: 760 × 0.0135951 = 10.3323 mH₂O.
Result760 mmHg = 10.3323 mH₂O

Conversion table

mmHgmH₂O
10.013595
20.02719
50.067976
100.13595
200.2719
500.67976
1001.3595
2002.719
5006.7976
100013.595

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from mmHg to mH₂O?
1 mmHg equals 0.0135951 mH₂O. To convert, multiply the value in millimetres of mercury by 0.0135951.
How do I convert 1 mmHg to mH₂O?
1 mmHg = 0.0135951 mH₂O. For any value, multiply by 0.0135951.
How do I convert mH₂O back to mmHg?
Divide by the same factor — or equivalently, multiply by 73.55591. So 1 mH₂O = 73.5559 mmHg.
When would I need to convert millimetre of mercury to metre of water column?
Pressure conversions between mmHg and mH₂O 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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