inHg to mmHg Converter

How to convert inches of mercury to millimeters of mercury

FormulammHg = inHg × 25.4

Multiply the value in inches of mercury by 25.4. To go the other way, multiply by 0.03937007874 (or divide by 25.4).

An inch of mercury is larger than a millimeter of mercury: one inch of mercury contains 25.4 millimeters of mercury.

Worked examples

1 inch of mercury1 inHg × 25.4 = 25.4 mmHg
5 inches of mercury5 inHg × 25.4 = 127 mmHg
10 inches of mercury10 inHg × 25.4 = 254 mmHg
20 inches of mercury20 inHg × 25.4 = 508 mmHg
100 inches of mercury100 inHg × 25.4 = 2,540 mmHg

Inches of mercury to millimeters of mercury conversion table

Values are calculated by the conversion engine and rounded to 8 significant figures.

Inches of mercury to millimeters of mercury: 0.1–10 inHg
Inches of mercury (inHg)	Millimeters of mercury (mmHg)
0.1 inHg	2.54 mmHg
0.25 inHg	6.35 mmHg
0.5 inHg	12.7 mmHg
1 inHg	25.4 mmHg
2 inHg	50.8 mmHg
3 inHg	76.2 mmHg
4 inHg	101.6 mmHg
5 inHg	127 mmHg
6 inHg	152.4 mmHg
7 inHg	177.8 mmHg
8 inHg	203.2 mmHg
9 inHg	228.6 mmHg
10 inHg	254 mmHg

Inches of mercury to millimeters of mercury: 12–1,000 inHg
Inches of mercury (inHg)	Millimeters of mercury (mmHg)
12 inHg	304.8 mmHg
15 inHg	381 mmHg
20 inHg	508 mmHg
25 inHg	635 mmHg
30 inHg	762 mmHg
40 inHg	1,016 mmHg
50 inHg	1,270 mmHg
75 inHg	1,905 mmHg
100 inHg	2,540 mmHg
250 inHg	6,350 mmHg
500 inHg	12,700 mmHg
1,000 inHg	25,400 mmHg

About the units

Inch of mercury (inHg)

About 3,386.39 Pa. US weather reports and aircraft altimeters use inches of mercury (standard is 29.92 inHg). One inch of mercury equals 3,386.38864 pascals (Pa).

Millimeter of mercury (mmHg)

The conventional mmHg is 133.322387415 Pa. Blood pressure is measured in mmHg (e.g. 120/80).

Frequently asked questions

How many millimeters of mercury are in one inch of mercury?

There are 25.4 millimeters of mercury in one inch of mercury, and this value is exact by definition.

How do I convert inches of mercury to millimeters of mercury?

Multiply the number of inches of mercury by 25.4. For example, 10 inHg × 25.4 = 254 mmHg.

How many inches of mercury are in one millimeter of mercury?

One millimeter of mercury equals 0.03937007874 inches of mercury. That is the reverse factor, 1 ÷ 25.4.

What is 10 inches of mercury in millimeters of mercury?

10 inHg = 254 mmHg.

Is this inHg to mmHg converter accurate?

Yes. Both units are defined exactly in terms of SI units, so the conversion factor is exact; results are shown to 12 significant figures by default and you can change precision in the converter. Calculations run in your browser using the same tested engine that generated this page.