Pressure
atmtomH₂O
Convert standard atmospheres (atm) to metres of water column (mH₂O).
Factor1 atm = 10.33227 mH₂O
Converter
atm
Accepts numbers or expressions, e.g. 150 + 14.7
Result
mH₂O
Rendered to 6 significant figures.
Formula
Formula
mH₂O = atm × 10.33227
Multiply any value in standard atmospheres by 10.33227 to obtain the value in metres of water column.
Worked example
Convert 1 atm to mH₂O.
- 01Start with 1 atm.
- 02Multiply by the conversion factor: 1 × 10.33227 = 10.3323 mH₂O.
Result1 atm = 10.3323 mH₂O
Conversion table
| atm | mH₂O |
|---|---|
| 1 | 10.332 |
| 2 | 20.665 |
| 5 | 51.661 |
| 10 | 103.32 |
| 20 | 206.65 |
| 50 | 516.61 |
| 100 | 1033.2 |
| 200 | 2066.5 |
| 500 | 5166.1 |
| 1000 | 10332 |
Reference values rounded to 5 significant figures for display.
FAQ
What is the conversion factor from atm to mH₂O?
1 atm equals 10.33227 mH₂O. To convert, multiply the value in standard atmospheres by 10.33227.
How do I convert 1 atm to mH₂O?
1 atm = 10.3323 mH₂O. For any value, multiply by 10.33227.
How do I convert mH₂O back to atm?
Divide by the same factor — or equivalently, multiply by 0.09678411. So 1 mH₂O = 0.0967841 atm.
When would I need to convert standard atmosphere to metre of water column?
Pressure conversions between atm and mH₂O 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).