Pressure
cmH₂OtohPa
Convert centimetres of water column (cmH₂O) to hectopascals (hPa).
Factor1 cmH₂O = 0.980665 hPa
Converter
cmH₂O
Accepts numbers or expressions, e.g. 150 + 14.7
Result
hPa
Rendered to 6 significant figures.
Formula
Formula
hPa = cmH₂O × 0.980665
Multiply any value in centimetres of water column by 0.980665 to obtain the value in hectopascals.
Worked example
Convert 10 cmH₂O to hPa.
- 01Start with 10 cmH₂O.
- 02Multiply by the conversion factor: 10 × 0.980665 = 9.80665 hPa.
Result10 cmH₂O = 9.80665 hPa
Conversion table
| cmH₂O | hPa |
|---|---|
| 1 | 0.98067 |
| 2 | 1.9613 |
| 5 | 4.9033 |
| 10 | 9.8067 |
| 20 | 19.613 |
| 50 | 49.033 |
| 100 | 98.066 |
| 200 | 196.13 |
| 500 | 490.33 |
| 1000 | 980.66 |
Reference values rounded to 5 significant figures for display.
FAQ
What is the conversion factor from cmH₂O to hPa?
1 cmH₂O equals 0.980665 hPa. To convert, multiply the value in centimetres of water column by 0.980665.
How do I convert 1 cmH₂O to hPa?
1 cmH₂O = 0.980665 hPa. For any value, multiply by 0.980665.
How do I convert hPa back to cmH₂O?
Divide by the same factor — or equivalently, multiply by 1.019716. So 1 hPa = 1.01972 cmH₂O.
When would I need to convert centimetre of water column to hectopascal?
Pressure conversions between cmH₂O 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).