Inches Of Mercury to Millimeters Of Mercury
Convert inches of mercury to millimeters of mercury instantly — one inch of mercury is 25.4 millimeters of mercury.
| Inches Of Mercury | Millimeters Of Mercury |
|---|---|
| 1 inHg | 25.400003 mmHg |
| 2 inHg | 50.800005 mmHg |
| 3 inHg | 76.200008 mmHg |
| 5 inHg | 127.000013 mmHg |
| 10 inHg | 254.000027 mmHg |
| 25 inHg | 635.000067 mmHg |
| 50 inHg | 1270.000135 mmHg |
| 100 inHg | 2540.00027 mmHg |
How to use
- Enter a value in the Inches Of Mercury field.
- The Millimeters Of Mercury figure appears immediately — no button to press.
- Typing in the Millimeters Of Mercury field converts back to Inches Of Mercury the same way.
- Use the reference table for the values that come up most often.
Inches Of Mercury to Millimeters Of Mercury formula
To convert inches of mercury to millimeters of mercury, multiply by 25.4000027.
mmHg = inHg × 25.4000027
Why this factor: the inch of mercury and the millimeter of mercury are both defined against the pascal, so dividing one definition by the other gives 25.4000027 directly. Both definitions are set out in full below.
To go the other way, divide by 25.4000027 — or use the Millimeters Of Mercury to Inches Of Mercury converter, which is the same calculation reversed.
Worked example
Given 760 inHg, multiplying by 25.4000027 yields 19304.00205 mmHg.
760 inHg × 25.4000027 = 19304.00205 mmHg
The converter above does this for any value you type, in either direction.
What is an inch of mercury?
An inch of mercury is the pressure of a one-inch mercury column, used for US barometric pressure.
Definition: About 3,386.389 pascals.
Where it is used: US weather barometric pressure, aircraft altimeter settings, and engine vacuum readings.
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.
Inches Of Mercury vs Millimeters Of Mercury
The inch of mercury is a US customary unit while the millimeter of mercury is a specialized unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many millimeters of mercury are in an inch of mercury?
One inch of mercury equals 25.4000027 millimeters of mercury.
What is the formula to convert inches of mercury to millimeters of mercury?
Multiply the number of inches of mercury by 25.4000027. To reverse it, divide by 25.4000027 instead.
How do I convert millimeters of mercury back to inches of mercury?
Divide by 25.4000027, which is the same as multiplying by 0.0393700746.
How many millimeters of mercury are in 10 inches of mercury?
10 inHg works out to 254.000027 mmHg.
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 inch of mercury defined?
About 3,386.389 pascals.