Pressure
atmtoftH₂O
Convert standard atmospheres (atm) to feet of water column (4 °C) (ftH₂O).
Factor1 atm = 33.89854 ftH₂O
Converter
atm
Accepts numbers or expressions, e.g. 150 + 14.7
Result
ftH₂O
Rendered to 6 significant figures.
Formula
Formula
ftH₂O = atm × 33.89854
Multiply any value in standard atmospheres by 33.89854 to obtain the value in feet of water column (4 °C).
Worked example
Convert 1 atm to ftH₂O.
- 01Start with 1 atm.
- 02Multiply by the conversion factor: 1 × 33.89854 = 33.8985 ftH₂O.
Result1 atm = 33.8985 ftH₂O
Conversion table
| atm | ftH₂O |
|---|---|
| 1 | 33.899 |
| 2 | 67.797 |
| 5 | 169.49 |
| 10 | 338.99 |
| 20 | 677.97 |
| 50 | 1694.9 |
| 100 | 3389.9 |
| 200 | 6779.7 |
| 500 | 16949 |
| 1000 | 33899 |
Reference values rounded to 5 significant figures for display.
FAQ
What is the conversion factor from atm to ftH₂O?
1 atm equals 33.89854 ftH₂O. To convert, multiply the value in standard atmospheres by 33.89854.
How do I convert 1 atm to ftH₂O?
1 atm = 33.8985 ftH₂O. For any value, multiply by 33.89854.
How do I convert ftH₂O back to atm?
Divide by the same factor — or equivalently, multiply by 0.0294998. So 1 ftH₂O = 0.0294998 atm.
When would I need to convert standard atmosphere to foot of water column (4 °C)?
Pressure conversions between atm and ftH₂O 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).