Table Of Contents
Inch of mercury to millimeters of mercury Conversion
1 inch of mercury (inHg) is equal to 25.4 millimeters of mercury (mmHg).
1 inHg = 25.4 mmHg
or
1 mmHg = 0.03937007874 inHg
Formula
To convert a pressure from inch of mercury (inHg) to millimeters of mercury (mmHg), multiply the pressure in inch of mercury by 25.4
p(mmHg) = p(inHg) × 25.4
Examples:
Convert 50 inch of mercury to millimeters of mercury:
p(mmHg) = 50inHg × 25.4 = 1270 mmHg
Conversion table
| Inch of mercury (inHg) | Millimeters of mercury (mmHg) |
|---|---|
| 1 inHg | 25.4 mmHg |
| 2 inHg | 50.8 mmHg |
| 3 inHg | 76.2 mmHg |
| 5 inHg | 127 mmHg |
| 10 inHg | 254 mmHg |
| 20 inHg | 508 mmHg |
| 25 inHg | 635 mmHg |
| 50 inHg | 1270 mmHg |
| 100 inHg | 2540 mmHg |
| 250 inHg | 6350 mmHg |
| 500 inHg | 12700 mmHg |
| 1000 inHg | 25400 mmHg |
| Millimeters of mercury (mmHg) | Inch of mercury (inHg) |
|---|---|
| 1 mmHg | 0.039370079 inHg |
| 2 mmHg | 0.078740157 inHg |
| 3 mmHg | 0.118110236 inHg |
| 5 mmHg | 0.196850394 inHg |
| 10 mmHg | 0.393700787 inHg |
| 20 mmHg | 0.787401575 inHg |
| 25 mmHg | 0.984251969 inHg |
| 50 mmHg | 1.968503937 inHg |
| 100 mmHg | 3.937007874 inHg |
| 250 mmHg | 9.842519685 inHg |
| 500 mmHg | 19.68503937 inHg |
| 1000 mmHg | 39.37007874 inHg |
Frequently asked questions
How do I convert inch of mercury to millimeters of mercury?
Multiply the value in inch of mercury by 25.4 to get the result in millimeters of mercury. For example, 5 inHg × 25.4 = 127 mmHg.
How many millimeters of mercury are in 1 inch of mercury?
1 inch of mercury (inHg) is equal to 25.4 millimeters of mercury (mmHg).
How do I convert millimeters of mercury back to inch of mercury?
Use the inverse operation: divide the value in millimeters of mercury by 25.4 to get the result in inch of mercury.
How accurate is the inch of mercury to millimeters of mercury conversion?
The converter multiplies by the conversion factor 25.4 and rounds the result to 9 decimal places by default. You can increase or reduce the precision with the digits option on this page.
Sources
Conversion factors are based on internationally recognised standards:
- BIPM — The International System of Units (SI Brochure, 9th edition)
- ISO 80000-4:2019 — Quantities and units — Part 4: Mechanics
- NIST Guide to the SI, Appendix B.8: Factors for Units Listed Alphabetically (NIST SP 811, 2008 edition)
- Resolution 4 of the 10th CGPM (1954): Definition of the standard atmosphere
