Inches of Water to Atmospheres (inH₂O → atm)
Formula
1 inH₂O = 0.002458248211201579 atmConversion Table
| inH₂O | atm |
|---|---|
| 0 | 0 |
| 1.0000 | 0.0024582 |
| 2.0000 | 0.0049165 |
| 3.0000 | 0.0073747 |
| 4.0000 | 0.0098330 |
| 5.0000 | 0.012291 |
| 6.0000 | 0.014749 |
| 7.0000 | 0.017208 |
| 8.0000 | 0.019666 |
| 9.0000 | 0.022124 |
| 10.000 | 0.024582 |
| 11.000 | 0.027041 |
| 12.000 | 0.029499 |
| 13.000 | 0.031957 |
| 14.000 | 0.034415 |
| 15.000 | 0.036874 |
| 16.000 | 0.039332 |
| 17.000 | 0.041790 |
| 18.000 | 0.044248 |
| 19.000 | 0.046707 |
| inH₂O | atm |
|---|---|
| 20.000 | 0.049165 |
| 21.000 | 0.051623 |
| 22.000 | 0.054081 |
| 23.000 | 0.056540 |
| 24.000 | 0.058998 |
| 25.000 | 0.061456 |
| 26.000 | 0.063914 |
| 27.000 | 0.066373 |
| 28.000 | 0.068831 |
| 29.000 | 0.071289 |
| 30.000 | 0.073747 |
| 31.000 | 0.076206 |
| 32.000 | 0.078664 |
| 33.000 | 0.081122 |
| 34.000 | 0.083580 |
| 35.000 | 0.086039 |
| 36.000 | 0.088497 |
| 37.000 | 0.090955 |
| 38.000 | 0.093413 |
| 39.000 | 0.095872 |
| inH₂O | atm |
|---|---|
| 40.000 | 0.098330 |
| 41.000 | 0.10079 |
| 42.000 | 0.10325 |
| 43.000 | 0.10570 |
| 44.000 | 0.10816 |
| 45.000 | 0.11062 |
| 46.000 | 0.11308 |
| 47.000 | 0.11554 |
| 48.000 | 0.11800 |
| 49.000 | 0.12045 |
| 50.000 | 0.12291 |
| 51.000 | 0.12537 |
| 52.000 | 0.12783 |
| 53.000 | 0.13029 |
| 54.000 | 0.13275 |
| 55.000 | 0.13520 |
| 56.000 | 0.13766 |
| 57.000 | 0.14012 |
| 58.000 | 0.14258 |
| 59.000 | 0.14504 |
| inH₂O | atm |
|---|---|
| 60.000 | 0.14749 |
| 61.000 | 0.14995 |
| 62.000 | 0.15241 |
| 63.000 | 0.15487 |
| 64.000 | 0.15733 |
| 65.000 | 0.15979 |
| 66.000 | 0.16224 |
| 67.000 | 0.16470 |
| 68.000 | 0.16716 |
| 69.000 | 0.16962 |
| 70.000 | 0.17208 |
| 71.000 | 0.17454 |
| 72.000 | 0.17699 |
| 73.000 | 0.17945 |
| 74.000 | 0.18191 |
| 75.000 | 0.18437 |
| 76.000 | 0.18683 |
| 77.000 | 0.18929 |
| 78.000 | 0.19174 |
| 79.000 | 0.19420 |
Inches of Water to Atmospheres Conversion
Converting Inches of Water (inH₂O) to Atmospheres (atm) is a common pressure conversion. 1 inH₂O equals 0.002458 atm. For example, 100 inH₂O is equal to 0.245825 atm.
Quick Mental Math: Inches of Water to Atmospheres
Divide inches-of-water by approximately 406.78 to convert to atmospheres.
Why is converting Inches of Water to Atmospheres tricky?
The non-integer divisor 406.78 requires careful mental arithmetic.
Quick Reference Values
1 inH₂O = 0.002458 atm. 5 inH₂O = 0.012291 atm. 10 inH₂O = 0.024582 atm. 25 inH₂O = 0.061456 atm. 50 inH₂O = 0.122912 atm. 100 inH₂O = 0.245825 atm.
What is Inches of Water?
Inches of Water (inH₂O) is a unit of pressure. Inches of water measure pressure as the height in inches of a water column. One inch of water equals 249.0889 pascals (Pa) at 4 °C. This unit is widely used to measure low-pressure differentials in HVAC and fluid systems [nist-si-guide]. The use of water columns for pressure measurement dates to early fluid mechanics studies. The inch unit was adopted in English-speaking countries for practical low-pressure measurement. It remains standardized for building and industrial applications [nist-si-guide]. Inches of water are used primarily in the United States for HVAC duct pressures, gas pressure measurements, and cleanroom environments. Other countries often use pascals or millimeters of water but recognize inH2O in specific sectors [nist-si-guide].
What is Atmospheres?
Atmospheres (atm) is a unit of pressure. One atmosphere (atm) is a unit of pressure defined as exactly 101,325 pascals (Pa). It approximates the average air pressure at sea level on Earth. The atmosphere unit is used for expressing pressures in meteorology and engineering [iso-80000]. The atmosphere was originally defined in the 19th century based on average sea-level air pressure. It was standardized by the International Union of Pure and Applied Chemistry (IUPAC) and other bodies to equal 101,325 Pa in the mid-20th century [nist-sp-811]. Atmospheres are used worldwide in scientific fields, including chemistry and physics, and in engineering applications like pressure vessel design. It is less common in everyday use outside these fields [nist-sp-811].
Common Misspellings
People often search for this conversion using these alternate spellings: inch of water, inch-water, in h2o, inch h20, atmosphers, atmosfere, atmospere, atmospherics. All of these refer to the Inches of Water to Atmospheres conversion.