mmH2O to Atmosphere Converter
Pressure · unit-converter
Convert mmH2O to Atmosphere with a fixed input and output unit, step-by-step formula line, and reference tables. All calculations bridge through pascal with fixed definitions (standard atmosphere = 101,325 Pa; torr and mmHg = atm/760; plus industrial/manometer units like kgf/cm², inHg, inH2O, and mmH2O).
About mmH2O
Millimeters of water column (mmH2O) is used for very low differential pressure in instrumentation and ventilation.
About Atmosphere
The standard atmosphere (atm) is defined as exactly 101,325 Pa. It links legacy chemistry and physics problems to SI.
How to convert millimeter of water (mmh2o, 4 °c) to atmosphere
1 mmh2o equals 0.00009678411053540586 atmosphere in this tool (via pascal):
1 mmh2o = (9.80665 Pa ÷ 101325 Pa) atm = 0.00009678411053540586 atm
Each mmh2o carries 9.80665 Pa and each atmosphere 101325 Pa, so one mmh2o equals 9.80665 ÷ 101325 atm.
Let p(mmh2o) be pressure in mmH2O (mmh2o), and p(atm) in Atmosphere (atm). Then:
p(atm) = p(mmh2o) × (9.80665 / 101325)
Equivalently, divide by how many mmh2o fit into one atm (Pa per atm divided by Pa per mmh2o):
p(atm) = p(mmh2o) ÷ 10332.27452799886
Examples
Example #1: Convert 1 mmh2o to atmosphere
1 mmh2o = 1 mmh2o × (9.80665/101325) atm = 0.0000967841 atm
1 mmh2o = 1 mmh2o ÷ 10332.27452799886 = 0.0000967841 atm
1 mmh2o × (9.80665/101,325) = 0.000097 atm
Example #2: Convert 10 mmh2o to atmosphere
10 mmh2o = 10 mmh2o × (9.80665/101325) atm = 0.0009678411 atm
10 mmh2o = 10 mmh2o ÷ 10332.27452799886 = 0.0009678411 atm
10 mmh2o × (9.80665/101,325) = 0.000968 atm
Summary
To convert mmH2O to Atmosphere, multiply the value in mmh2o by (9.80665 Pa per mmh2o) / (101325 Pa per atm). Equivalently: value_atm = value_mmh2o × (9.80665 / 101325). Numerically, 1 mmh2o equals 0.00009678411053540586 atm.
Relationship context
Both mmH2O and Atmosphere are converted by fixed multiples of the pascal. Multiplying by (Pa per mmh2o) ÷ (Pa per atm) gives the same result as passing through pascal, keeping bar, atm, PSI, kPa, hPa, torr, and mmHg consistent on the hub.
Conversion tables
| mmH2O (mmh2o) | Atmosphere (atm) |
|---|---|
| 0.1 | 0.0000096784 |
| 1 | 0.0000967841 |
| 2 | 0.0001935682 |
| 3 | 0.0002903523 |
| 4 | 0.0003871364 |
| 5 | 0.0004839206 |
| 6 | 0.0005807047 |
| 7 | 0.0006774888 |
| 8 | 0.0007742729 |
| 9 | 0.000871057 |
| mmH2O (mmh2o) | Atmosphere (atm) |
|---|---|
| 10 | 0.0009678411 |
| 20 | 0.0019356822 |
| 30 | 0.0029035233 |
| 40 | 0.0038713644 |
| 50 | 0.0048392055 |
| 60 | 0.0058070466 |
| 70 | 0.0067748877 |
| 80 | 0.0077427288 |
| 90 | 0.0087105699 |
| 100 | 0.0096784111 |