Inches of mercury.
inHgs to Atmospheres Converter — inHg to atm
Convert inHg (inHg) to Atmosphere (atm) using the exact conversion factor (1 inhg = 0.0334210609 atmosphere). See the formula, worked examples, conversion table, and common uses.
inHgs to Atmospheres converter
Converter
Pressure Converter
Convert pascals, bars, PSI, atmospheres, mercury columns, water columns, and engineering pressure units.
Context values
Some unit families need one extra value for a physically accurate result.
A standard atmosphere is exactly 101,325 pascals.
Result = input x 3386.389 / 101325.
Pressure uses the pascal as the base unit.
Reserved above the conversion cards and below the converter.
About Converting inHgs to Atmospheres
inHg and Atmosphere both show up on pressure gauges — psi is standard on US tire and tool specifications, while bar is the everyday pressure unit across most of the rest of the world. Specifically: Inches of mercury, and a standard atmosphere is exactly 101,325 pascals.
Formula
atmospheres = inhgs × 0.0334210609425
This factor comes from each unit's defined relationship to the category's base unit: 1 inhg equals 3386.389 base units, and 1 atmosphere equals 101325 base units, so dividing one by the other gives the direct inhg-to-atmosphere factor of 0.0334210609425.
Simple example
1 inHg × 0.03342106094 = 0.0334210609 atm
1 inhg = 0.0334210609 atmospheres.
Real-world example
35 inHg × 0.03342106094 = 1.169737133 atm
35 inhgs = 1.169737133 atmospheres.
Conversion table
| inHg (inHg) | Atmosphere (atm) |
|---|---|
| 1 inHg | 0.0334210609 atm |
| 5 inHg | 0.1671053047 atm |
| 10 inHg | 0.3342106094 atm |
| 25 inHg | 0.8355265236 atm |
| 50 inHg | 1.671053047 atm |
| 100 inHg | 3.342106094 atm |
Reverse conversion: Atmosphere to inHg
0.0334210609 atm × 29.9212524 = 0.9999999987 inHg
0.0334210609 atmospheres = 0.9999999987 inhgs.
inhgs = atmospheres × 29.9212524019
For a page dedicated to this direction, see Atmosphere to inHg.
Understanding the inHg (inHg)
Inches of mercury.
Understanding the Atmosphere
Atmosphere (atm) measures pressure. Defined as exactly 101,325 pascals, originally based on the average atmospheric pressure at mean sea level. It is classified as a non-SI unit accepted for use with the SI.
Where it's used: Widely used internationally in chemistry, meteorology, and diving/aviation contexts alongside the pascal and bar
Uses of the Atmosphere today
- Chemistry (standard conditions are often defined at 1 atm)
- Diving and aviation pressure references
- General reference for everyday atmospheric pressure
Atmosphere — sources
- BIPM SI Brochure — Standard atmosphere listed among non-SI units with a fixed exact value in pascals.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many atmospheres are in 1 inhg?
1 inhg equals 0.0334210609 atmospheres, using the exact defined conversion factor rather than an estimate.
How do I convert inhg to atmosphere?
Multiply the inhg value by 0.03342106094. The converter above does this instantly to whatever precision you set.
How do I convert atmosphere back to inhg?
Use the reverse factor: 1 atmosphere equals 29.9212524 inhgs. You can also use the swap control in the converter above to flip the direction instantly.
What is a inhg?
inHg (inHg) is a unit of pressure.
What is a atmosphere?
Atmosphere (atm) measures pressure. Defined as exactly 101,325 pascals, originally based on the average atmospheric pressure at mean sea level. It is classified as a non-SI unit accepted for use with the SI.
Is the inhg to atmosphere conversion exact?
Yes. Defined as exactly 101,325 pascals, originally based on the average atmospheric pressure at mean sea level. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.