Pressure
mH₂OtoinHg
Convert metres of water column (mH₂O) to inches of mercury (0 °C) (inHg).
Factor1 mH₂O = 2.895902 inHg
Converter
mH₂O
Accepts numbers or expressions, e.g. 150 + 14.7
Result
inHg
Rendered to 6 significant figures.
Formula
Formula
inHg = mH₂O × 2.895902
Multiply any value in metres of water column by 2.895902 to obtain the value in inches of mercury (0 °C).
Worked example
Convert 1 mH₂O to inHg.
- 01Start with 1 mH₂O.
- 02Multiply by the conversion factor: 1 × 2.895902 = 2.8959 inHg.
Result1 mH₂O = 2.8959 inHg
Conversion table
| mH₂O | inHg |
|---|---|
| 1 | 2.8959 |
| 2 | 5.7918 |
| 5 | 14.48 |
| 10 | 28.959 |
| 20 | 57.918 |
| 50 | 144.8 |
| 100 | 289.59 |
| 200 | 579.18 |
| 500 | 1448 |
| 1000 | 2895.9 |
Reference values rounded to 5 significant figures for display.
FAQ
What is the conversion factor from mH₂O to inHg?
1 mH₂O equals 2.895902 inHg. To convert, multiply the value in metres of water column by 2.895902.
How do I convert 1 mH₂O to inHg?
1 mH₂O = 2.8959 inHg. For any value, multiply by 2.895902.
How do I convert inHg back to mH₂O?
Divide by the same factor — or equivalently, multiply by 0.3453156. So 1 inHg = 0.345316 mH₂O.
When would I need to convert metre of water column to inch of mercury (0 °C)?
Pressure conversions between mH₂O 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).