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Pressure

ftH₂OtoinHg

Convert feet of water column (4 °C) (ftH₂O) to inches of mercury (0 °C) (inHg).

Factor1 ftH₂O = 0.8826709 inHg

Converter

ftH₂O

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

Result
88.2671inHg

Rendered to 6 significant figures.

Formula

Formula
inHg = ftH₂O × 0.8826709

Multiply any value in feet of water column (4 °C) by 0.8826709 to obtain the value in inches of mercury (0 °C).

Worked example

Convert 100 ftH₂O to inHg.

  1. 01Start with 100 ftH₂O.
  2. 02Multiply by the conversion factor: 100 × 0.8826709 = 88.2671 inHg.
Result100 ftH₂O = 88.2671 inHg

Conversion table

ftH₂OinHg
10.88267
21.7653
54.4134
108.8267
2017.653
5044.134
10088.267
200176.53
500441.34
1000882.67

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from ftH₂O to inHg?
1 ftH₂O equals 0.8826709 inHg. To convert, multiply the value in feet of water column (4 °C) by 0.8826709.
How do I convert 1 ftH₂O to inHg?
1 ftH₂O = 0.882671 inHg. For any value, multiply by 0.8826709.
How do I convert inHg back to ftH₂O?
Divide by the same factor — or equivalently, multiply by 1.132925. So 1 inHg = 1.13293 ftH₂O.
When would I need to convert foot of water column (4 °C) to inch of mercury (0 °C)?
Pressure conversions between ftH₂O 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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