Millimeters Of Mercury to Atmospheres
Type a value in either box to convert between millimeters of mercury and atmospheres. The factor is 0.00131579.
| Millimeters Of Mercury | Atmospheres |
|---|---|
| 1 mmHg | 0.001316 atm |
| 2 mmHg | 0.002632 atm |
| 3 mmHg | 0.003947 atm |
| 5 mmHg | 0.006579 atm |
| 10 mmHg | 0.013158 atm |
| 25 mmHg | 0.032895 atm |
| 50 mmHg | 0.065789 atm |
| 100 mmHg | 0.131579 atm |
How to use
- Enter a value in the Millimeters Of Mercury field.
- The Atmospheres figure appears immediately — no button to press.
- Typing in the Atmospheres field converts back to Millimeters Of Mercury the same way.
- Use the reference table for the values that come up most often.
Millimeters Of Mercury to Atmospheres formula
Converting millimeters of mercury to atmospheres is a single multiplication by 0.00131578966.
atm = mmHg × 0.00131578966
Why this factor: the millimeter of mercury and the atmosphere are both defined against the pascal, so dividing one definition by the other gives 0.00131578966 directly. Both definitions are set out in full below.
To go the other way, divide by 0.00131578966 — or use the Atmospheres to Millimeters Of Mercury converter, which is the same calculation reversed.
Worked example
Given 760 mmHg, multiplying by 0.00131578966 yields 1 atm.
760 mmHg × 0.00131578966 = 1 atm
The converter above does this for any value you type, in either direction.
What is a millimeter of mercury?
A millimeter of mercury is the pressure exerted by a 1 mm column of mercury, still standard in medicine.
Definition: Defined as exactly 133.322387415 pascals.
Where it is used: Blood pressure readings, intraocular pressure, and respiratory gas pressures.
Worth knowing: Blood pressure is universally reported in mmHg even in fully metric countries — one of the most durable legacy units in medicine.
What is an atmosphere?
A standard atmosphere is a fixed reference pressure, originally average sea-level air pressure.
Definition: Defined as exactly 101,325 pascals — an exact convention, not a measurement.
Where it is used: Chemistry reference conditions, diving pressure, and high-pressure physics.
Millimeters Of Mercury vs Atmospheres
The millimeter of mercury and the atmosphere belong to the same family of units, so converting between them is usually a matter of shifting a decimal point or applying a small whole-number factor.
Frequently asked questions
How many atmospheres are in a millimeter of mercury?
One millimeter of mercury equals 0.00131578966 atmospheres.
What is the formula to convert millimeters of mercury to atmospheres?
Multiply the number of millimeters of mercury by 0.00131578966. To reverse it, divide by 0.00131578966 instead.
How do I convert atmospheres back to millimeters of mercury?
Divide by 0.00131578966, which is the same as multiplying by 759.999892.
How many atmospheres are in 10 millimeters of mercury?
10 mmHg works out to 0.013158 atm.
Is there anything to watch out for with millimeters of mercury?
Blood pressure is universally reported in mmHg even in fully metric countries — one of the most durable legacy units in medicine.
How is the millimeter of mercury defined?
Defined as exactly 133.322387415 pascals.