Pressure
inH₂OtokPa
Convert inches of water column (4 °C) (inH₂O) to kilopascals (kPa).
Factor1 inH₂O = 0.2490889 kPa
Converter
inH₂O
Accepts numbers or expressions, e.g. 150 + 14.7
Result
kPa
Rendered to 6 significant figures.
Formula
Formula
kPa = inH₂O × 0.2490889
Multiply any value in inches of water column (4 °C) by 0.2490889 to obtain the value in kilopascals.
Worked example
Convert 100 inH₂O to kPa.
- 01Start with 100 inH₂O.
- 02Multiply by the conversion factor: 100 × 0.2490889 = 24.9089 kPa.
Result100 inH₂O = 24.9089 kPa
Conversion table
| inH₂O | kPa |
|---|---|
| 1 | 0.24909 |
| 2 | 0.49818 |
| 5 | 1.2454 |
| 10 | 2.4909 |
| 20 | 4.9818 |
| 50 | 12.454 |
| 100 | 24.909 |
| 200 | 49.818 |
| 500 | 124.54 |
| 1000 | 249.09 |
Reference values rounded to 5 significant figures for display.
FAQ
What is the conversion factor from inH₂O to kPa?
1 inH₂O equals 0.2490889 kPa. To convert, multiply the value in inches of water column (4 °C) by 0.2490889.
How do I convert 1 inH₂O to kPa?
1 inH₂O = 0.249089 kPa. For any value, multiply by 0.2490889.
How do I convert kPa back to inH₂O?
Divide by the same factor — or equivalently, multiply by 4.014631. So 1 kPa = 4.01463 inH₂O.
When would I need to convert inch of water column (4 °C) to kilopascal?
Pressure conversions between inH₂O and kPa 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).