Pressure
atmtoinHg
Convert standard atmospheres (atm) to inches of mercury (0 °C) (inHg).
Factor1 atm = 29.92125 inHg
Converter
atm
Accepts numbers or expressions, e.g. 150 + 14.7
Result
inHg
Rendered to 6 significant figures.
Formula
Formula
inHg = atm × 29.92125
Multiply any value in standard atmospheres by 29.92125 to obtain the value in inches of mercury (0 °C).
Worked example
Convert 1 atm to inHg.
- 01Start with 1 atm.
- 02Multiply by the conversion factor: 1 × 29.92125 = 29.9213 inHg.
Result1 atm = 29.9213 inHg
Conversion table
| atm | inHg |
|---|---|
| 1 | 29.921 |
| 2 | 59.843 |
| 5 | 149.61 |
| 10 | 299.21 |
| 20 | 598.43 |
| 50 | 1496.1 |
| 100 | 2992.1 |
| 200 | 5984.3 |
| 500 | 14961 |
| 1000 | 29921 |
Reference values rounded to 5 significant figures for display.
FAQ
What is the conversion factor from atm to inHg?
1 atm equals 29.92125 inHg. To convert, multiply the value in standard atmospheres by 29.92125.
How do I convert 1 atm to inHg?
1 atm = 29.9213 inHg. For any value, multiply by 29.92125.
How do I convert inHg back to atm?
Divide by the same factor — or equivalently, multiply by 0.03342106. So 1 inHg = 0.0334211 atm.
When would I need to convert standard atmosphere to inch of mercury (0 °C)?
Pressure conversions between atm and inHg are common when working with mixed-vendor instrumentation, when piping codes use different units to process datasheets, or when converting field readings into SI for hydraulic calculations.
Is the conversion exact?
The factor shown is precise to at least 7 significant figures. For most process-engineering work this is far better than instrument accuracy. For metrology or trade applications, refer to the relevant national standard (NIST, BIPM, ISO 80000).