Atmospheres to millimeters of mercury
Type a value in atmospheres to see it in millimeters of mercury straight away, or type in the second box to convert back.
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How to use it
- Type the value in the atmospheres box.
- Read the result in millimeters of mercury as you type, and pick the precision you need.
- Swap the direction to convert back, or copy the result.
How it is calculated
mmHg = atm × 759.9998917
Multiply the value in atmospheres by 759.9998917 to get millimeters of mercury.
Example
To convert 25 atm to millimeters of mercury: 25 × 759.9998917 = 19,000 mmHg.
Conversion table
| Atmospheres (atm) | Millimeters of mercury (mmHg) |
|---|---|
| 1 | 760 |
| 2 | 1,520 |
| 3 | 2,280 |
| 5 | 3,800 |
| 10 | 7,600 |
| 20 | 15,200 |
| 25 | 19,000 |
| 50 | 38,000 |
| 100 | 76,000 |
| 250 | 190,000 |
| 500 | 380,000 |
| 1,000 | 760,000 |
About the units
- Atmosphere
- The standard atmosphere, defined as exactly 101,325 pascals.
- Millimeter of mercury
- The pressure of a 1 mm mercury column at the conventional density 13,595.1 kg/m³ and standard gravity: 133.322387415 Pa. Used for blood pressure.
Limits and caveats
- Results are rounded for display and computed with the browser's floating point precision (about 15 significant digits).
- Both unit factors are exact by their official definitions.
Questions about this tool
How many millimeters of mercury are in one atmosphere?
1 atm = 760 mmHg exactly.
How do I convert atmospheres to millimeters of mercury?
Use mmHg = atm × 759.9998917. For example, 25 atm = 19,000 mmHg.
How many atmospheres are in one millimeter of mercury?
1 mmHg = 0.00131579 atm.
What is the difference between gauge and absolute pressure?
Gauge pressure is measured from the surrounding air pressure, while absolute pressure starts from a perfect vacuum. These converters change the unit only, so a gauge reading stays a gauge reading.
Are torr and mmHg the same?
Almost. One torr is 101325/760 Pa, about 133.322368 Pa, and one conventional mmHg is 133.322387 Pa, a difference of less than one part per million. For everyday use you can treat them as equal.