Inches Of Mercury to Torr
Convert inches of mercury to torr instantly — one inch of mercury is 25.4 torr.
| Inches Of Mercury | Torr |
|---|---|
| 1 inHg | 25.400006 Torr |
| 2 inHg | 50.800013 Torr |
| 3 inHg | 76.200019 Torr |
| 5 inHg | 127.000032 Torr |
| 10 inHg | 254.000063 Torr |
| 25 inHg | 635.000158 Torr |
| 50 inHg | 1270.000316 Torr |
| 100 inHg | 2540.000632 Torr |
How to use
- Enter a value in the Inches Of Mercury field.
- The Torr figure appears immediately — no button to press.
- Typing in the Torr 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 Torr formula
The factor from inches of mercury to torr is 25.4000063.
Torr = inHg × 25.4000063
Why this factor: the inch of mercury and the torr are both defined against the pascal, so dividing one definition by the other gives 25.4000063 directly. Both definitions are set out in full below.
To go the other way, divide by 25.4000063 — or use the Torr to Inches Of Mercury converter, which is the same calculation reversed.
Worked example
Given 32 inHg, multiplying by 25.4000063 yields 812.800202 Torr.
32 inHg × 25.4000063 = 812.800202 Torr
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 torr?
A torr is a vacuum-measurement pressure unit, defined as one 760th of a standard atmosphere.
Definition: Exactly 101,325/760 pascals, which is about 133.3224 Pa. Named after Evangelista Torricelli.
Where it is used: Vacuum systems, mass spectrometry, and semiconductor process chambers.
Worth knowing: Almost identical to the mmHg but not exactly equal — they differ by about one part in seven million, which matters only in precision metrology.
Inches Of Mercury vs Torr
The inch of mercury is a US customary unit while the torr 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 torr are in an inch of mercury?
One inch of mercury equals 25.4000063 torr.
What is the formula to convert inches of mercury to torr?
Multiply the number of inches of mercury by 25.4000063. To reverse it, divide by 25.4000063 instead.
How do I convert torr back to inches of mercury?
Divide by 25.4000063, which is the same as multiplying by 0.0393700689.
How many torr are in 10 inches of mercury?
10 inHg works out to 254.000063 Torr.
Is there anything to watch out for with torr?
Almost identical to the mmHg but not exactly equal — they differ by about one part in seven million, which matters only in precision metrology.
How is the inch of mercury defined?
About 3,386.389 pascals.