This converter turns inches of mercury into torr instantly, using the exact factor 1 inch of mercury = 25.40000632 torr. Type any number and the result updates as you go — nothing is sent to a server, so the arithmetic happens entirely in your browser.
US aviation and weather altimeter setting unit. One millimetre of mercury, used in vacuum work.
Because the relationship is a simple proportion, one multiplication does the whole job. The table further down gives pre-computed values for the amounts people look up most often, and the result panel also reports the reverse conversion so you can check the figure both ways.
The formula
inches of mercury- The amount you are converting, measured in inches of mercury
25.40000632- The exact number of torr in one inch of mercury
torr- The converted result
How it works, step by step
- Enter the number of inches of mercury you want to convert.
- The value is multiplied by 25.40000632, the exact conversion factor.
- The result is displayed in torr, rounded for readability.
- The unrounded value and the reverse conversion appear underneath so you can verify it.
Worked examples
Converting 5 inches of mercury
Multiply 5 by 25.400006. That gives 127 torr. A quick sanity check: one inch of mercury is larger than one torr, so the number should get bigger — and it does.
Converting 72 inches of mercury
72 × 25.400006 = 1,828.8 torr. Working backwards, 1,828.8 ÷ 25.400006 returns 72 inches of mercury, which confirms the factor is applied the right way round.
How to read your score
Frequently asked questions
How many torr are in one inch of mercury?
Exactly 25.40000632. Every conversion on this page is that single number multiplied by your input, so the result carries no rounding error beyond what is shown.
What is the formula to convert inches of mercury to torr?
Torr = inches of mercury × 25.40000632. To reverse it, divide instead: inches of mercury = torr ÷ 25.40000632, which is the same as multiplying by 0.03937006895.
Is the inch of mercury bigger than the torr?
Yes. One inch of mercury equals 25.4 torr, so it is the larger unit.
Why does my answer differ slightly from other inhg to torr converters?
Most differences come from rounding the factor too early. This tool keeps full double precision through the calculation and only rounds at the final display step, and it also shows the unrounded value so you can see exactly where any difference appears.
What is a inch of mercury?
US aviation and weather altimeter setting unit.
What is a torr?
One millimetre of mercury, used in vacuum work.
Inches Of Mercury to torr reference table
| Inches Of Mercury | Torr |
|---|---|
| 0.5 inHg | 12.7 Torr |
| 1 inHg | 25.4 Torr |
| 2 inHg | 50.8 Torr |
| 3 inHg | 76.2 Torr |
| 5 inHg | 127 Torr |
| 10 inHg | 254.0001 Torr |
| 15 inHg | 381.0001 Torr |
| 20 inHg | 508.0001 Torr |
| 25 inHg | 635.0002 Torr |
| 50 inHg | 1,270 Torr |
| 75 inHg | 1,905 Torr |
| 100 inHg | 2,540 Torr |
| 250 inHg | 6,350 Torr |
| 500 inHg | 12,700 Torr |
| 1000 inHg | 25,400.01 Torr |
Exact factor: 1 inch of mercury = 25.40000632 torr. Values rounded for display.