Table Of Contents
Inch of mercury to atmospheres Conversion
1 inch of mercury (inHg) is equal to 0.03342105739 atmospheres (atm).
1 inHg = 0.03342105739 atm
or
1 atm = 29.92125558 inHg
Formula
To convert a pressure from inch of mercury (inHg) to atmospheres (atm), divide the pressure in inch of mercury by 29.92125558
p(atm) = p(inHg) / 29.92125558
Examples:
Convert 10 inch of mercury to atmospheres:
p(atm) = 10inHg / 29.92125558 = 0.3342105739 atm
Conversion table
| Inch of mercury (inHg) | Atmospheres (atm) |
|---|---|
| 1 inHg | 0.033421057 atm |
| 2 inHg | 0.066842115 atm |
| 3 inHg | 0.100263172 atm |
| 5 inHg | 0.167105287 atm |
| 10 inHg | 0.334210574 atm |
| 20 inHg | 0.668421148 atm |
| 25 inHg | 0.835526435 atm |
| 50 inHg | 1.67105287 atm |
| 100 inHg | 3.342105739 atm |
| 250 inHg | 8.355264348 atm |
| 500 inHg | 16.710528696 atm |
| 1000 inHg | 33.421057393 atm |
| Atmospheres (atm) | Inch of mercury (inHg) |
|---|---|
| 1 atm | 29.92125558 inHg |
| 2 atm | 59.842511159 inHg |
| 3 atm | 89.763766739 inHg |
| 5 atm | 149.606277899 inHg |
| 10 atm | 299.212555797 inHg |
| 20 atm | 598.425111595 inHg |
| 25 atm | 748.031389494 inHg |
| 50 atm | 1496.062778987 inHg |
| 100 atm | 2992.125557975 inHg |
| 250 atm | 7480.313894937 inHg |
| 500 atm | 14960.627789874 inHg |
| 1000 atm | 29921.255579748 inHg |
Frequently asked questions
How do I convert inch of mercury to atmospheres?
Divide the value in inch of mercury by 29.92125558 to get the result in atmospheres. For example, 5 inHg ÷ 29.92125558 = 0.167105287 atm.
How many atmospheres are in 1 inch of mercury?
1 inch of mercury (inHg) is equal to 0.033421057 atmospheres (atm).
How do I convert atmospheres back to inch of mercury?
Use the inverse operation: multiply the value in atmospheres by 29.92125558 to get the result in inch of mercury.
How accurate is the inch of mercury to atmospheres conversion?
The converter multiplies by the conversion factor 29.92125558 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
