Direct conversion
Convert millimeter of water [mmH2O] to standard atmosphere [atm] instantly with formula, examples, chart, and FAQs.
1 millimeter of water [mmH2O] = 0.000097 standard atmosphere [atm]
1 millimeter of water [mmH2O] = 0.000097 standard atmosphere [atm]
Example: 1 millimeter of water [mmH2O] equals 0.000097 standard atmosphere [atm].
Pressure conversions use pascal as the reference unit and include common engineering, weather, tire, and laboratory pressure units.
Displayed results are rounded for readability. The calculator keeps enough precision for everyday use and switches to scientific notation for very large or very small values. Last reviewed: 2026-08-14.
The millimeter of water (mmH2O) is a pressure unit used to express measurements in this converter.
HistoryThis unit is included because it appears in practical measurement systems, technical references, product specifications, or everyday conversion needs.
Current useUse millimeter of water when comparing pressure values, checking specifications, converting between systems, or preparing quick estimates.
The standard atmosphere is a pressure unit equal to 101,325 pascals.
HistoryAtmosphere was defined around average sea-level air pressure for reference calculations.
Current useAtmospheres are used in chemistry, gas laws, diving references, and technical pressure comparisons.
| millimeter of water [mmH2O] | standard atmosphere [atm] |
|---|---|
| 1 | 0.000097 |
| 2 | 0.000194 |
| 5 | 0.000484 |
| 10 | 0.000968 |
| 20 | 0.001936 |
| 25 | 0.00242 |
| 50 | 0.004839 |
| 100 | 0.009678 |
| 1000 | 0.096784 |
Use this formula: 1 millimeter of water [mmH2O] = 0.000097 standard atmosphere [atm] Enter your value in the calculator and the result updates instantly.
1 millimeter of water [mmH2O] equals 0.000097 standard atmosphere [atm].
Yes. Use the swap button in the calculator or open the related reverse conversion link when it is listed on this page.