Pressure
ftH₂Otoatm
Convert feet of water column (4 °C) (ftH₂O) to standard atmospheres (atm).
Factor1 ftH₂O = 0.0294998 atm
Converter
ftH₂O
Accepts numbers or expressions, e.g. 150 + 14.7
Result
atm
Rendered to 6 significant figures.
Formula
Formula
atm = ftH₂O × 0.0294998
Multiply any value in feet of water column (4 °C) by 0.0294998 to obtain the value in standard atmospheres.
Worked example
Convert 33.9 ftH₂O to atm.
- 01Start with 33.9 ftH₂O.
- 02Multiply by the conversion factor: 33.9 × 0.0294998 = 1.00004 atm.
Result33.9 ftH₂O = 1.00004 atm
Conversion table
| ftH₂O | atm |
|---|---|
| 1 | 0.0295 |
| 2 | 0.059 |
| 5 | 0.1475 |
| 10 | 0.295 |
| 20 | 0.59 |
| 50 | 1.475 |
| 100 | 2.95 |
| 200 | 5.9 |
| 500 | 14.75 |
| 1000 | 29.5 |
Reference values rounded to 5 significant figures for display.
FAQ
What is the conversion factor from ftH₂O to atm?
1 ftH₂O equals 0.0294998 atm. To convert, multiply the value in feet of water column (4 °C) by 0.0294998.
How do I convert 1 ftH₂O to atm?
1 ftH₂O = 0.0294998 atm. For any value, multiply by 0.0294998.
How do I convert atm back to ftH₂O?
Divide by the same factor — or equivalently, multiply by 33.89854. So 1 atm = 33.8985 ftH₂O.
When would I need to convert foot of water column (4 °C) to standard atmosphere?
Pressure conversions between ftH₂O and atm 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).