Pressure
inHgtoatm
Convert inches of mercury (0 °C) (inHg) to standard atmospheres (atm).
Factor1 inHg = 0.03342106 atm
Converter
inHg
Accepts numbers or expressions, e.g. 150 + 14.7
Result
atm
Rendered to 6 significant figures.
Formula
Formula
atm = inHg × 0.03342106
Multiply any value in inches of mercury (0 °C) by 0.03342106 to obtain the value in standard atmospheres.
Worked example
Convert 30 inHg to atm.
- 01Start with 30 inHg.
- 02Multiply by the conversion factor: 30 × 0.03342106 = 1.00263 atm.
Result30 inHg = 1.00263 atm
Conversion table
| inHg | atm |
|---|---|
| 1 | 0.033421 |
| 2 | 0.066842 |
| 5 | 0.16711 |
| 10 | 0.33421 |
| 20 | 0.66842 |
| 50 | 1.6711 |
| 100 | 3.3421 |
| 200 | 6.6842 |
| 500 | 16.711 |
| 1000 | 33.421 |
Reference values rounded to 5 significant figures for display.
FAQ
What is the conversion factor from inHg to atm?
1 inHg equals 0.03342106 atm. To convert, multiply the value in inches of mercury (0 °C) by 0.03342106.
How do I convert 1 inHg to atm?
1 inHg = 0.0334211 atm. For any value, multiply by 0.03342106.
How do I convert atm back to inHg?
Divide by the same factor — or equivalently, multiply by 29.92125. So 1 atm = 29.9213 inHg.
When would I need to convert inch of mercury (0 °C) to standard atmosphere?
Pressure conversions between inHg and atm 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).