Pressure
inH₂OtohPa
Convert inches of water column (4 °C) (inH₂O) to hectopascals (hPa).
Factor1 inH₂O = 2.490889 hPa
Converter
inH₂O
Accepts numbers or expressions, e.g. 150 + 14.7
Result
hPa
Rendered to 6 significant figures.
Formula
Formula
hPa = inH₂O × 2.490889
Multiply any value in inches of water column (4 °C) by 2.490889 to obtain the value in hectopascals.
Worked example
Convert 100 inH₂O to hPa.
- 01Start with 100 inH₂O.
- 02Multiply by the conversion factor: 100 × 2.490889 = 249.089 hPa.
Result100 inH₂O = 249.089 hPa
Conversion table
| inH₂O | hPa |
|---|---|
| 1 | 2.4909 |
| 2 | 4.9818 |
| 5 | 12.454 |
| 10 | 24.909 |
| 20 | 49.818 |
| 50 | 124.54 |
| 100 | 249.09 |
| 200 | 498.18 |
| 500 | 1245.4 |
| 1000 | 2490.9 |
Reference values rounded to 5 significant figures for display.
FAQ
What is the conversion factor from inH₂O to hPa?
1 inH₂O equals 2.490889 hPa. To convert, multiply the value in inches of water column (4 °C) by 2.490889.
How do I convert 1 inH₂O to hPa?
1 inH₂O = 2.49089 hPa. For any value, multiply by 2.490889.
How do I convert hPa back to inH₂O?
Divide by the same factor — or equivalently, multiply by 0.4014631. So 1 hPa = 0.401463 inH₂O.
When would I need to convert inch of water column (4 °C) to hectopascal?
Pressure conversions between inH₂O and hPa 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).