Pounds per square inch.
PSI to Atmospheres Converter — psi to atm
Convert PSI (psi) to Atmosphere (atm) using the exact conversion factor (1 psi = 0.0680459639 atmosphere). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
PSI 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 6894.757293 / 101325.
Pressure uses the pascal as the base unit.
Reserved above the conversion cards and below the converter.
About Converting PSI to Atmospheres
PSI 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. PSI is typically associated with united States (standard pressure unit for tires, tools, and plumbing), while Atmosphere is typically associated with widely used internationally in chemistry, meteorology, and diving/aviation contexts alongside the pascal and bar.
Formula
atmospheres = psi × 0.0680459639099
This factor comes from each unit's defined relationship to the category's base unit: 1 psi equals 6894.75729317 base units, and 1 atmosphere equals 101325 base units, so dividing one by the other gives the direct psi-to-atmosphere factor of 0.0680459639099.
Simple example
1 psi × 0.06804596391 = 0.0680459639 atm
1 psi = 0.0680459639 atmospheres.
Real-world example
35 psi × 0.06804596391 = 2.381608737 atm
35 psi = 2.381608737 atmospheres.
Conversion table
| PSI (psi) | Atmosphere (atm) |
|---|---|
| 1 psi | 0.0680459639 atm |
| 5 psi | 0.3402298195 atm |
| 10 psi | 0.6804596391 atm |
| 25 psi | 1.701149098 atm |
| 50 psi | 3.402298195 atm |
| 100 psi | 6.804596391 atm |
Reverse conversion: Atmosphere to PSI
0.0680459639 atm × 14.69594878 = 0.9999999999 psi
0.0680459639 atmospheres = 0.9999999999 psi.
psi = atmospheres × 14.6959487755
For a page dedicated to this direction, see Atmosphere to PSI.
PSI vs. Atmosphere
| Aspect | PSI | Atmosphere |
|---|---|---|
| Family | US/imperial customary unit | non-SI unit accepted for use with the SI |
| Typical use | Tire pressure specifications in the US | Chemistry (standard conditions are often defined at 1 atm) |
| Where it's used | United States (standard pressure unit for tires, tools, and plumbing) | Widely used internationally in chemistry, meteorology, and diving/aviation contexts alongside the pascal and bar |
Understanding the PSI
PSI (psi) measures pressure. PSI (pounds-force per square inch) equals exactly 6,894.757293168 pascals. It is classified as a US/imperial customary unit.
Where it's used: United States (standard pressure unit for tires, tools, and plumbing)
Uses of the PSI today
- Tire pressure specifications in the US
- Hydraulic and pneumatic system ratings
- Plumbing, compressed-air tools, and industrial equipment ratings
History of the PSI
PSI is a derived unit from the pound-force and the inch, both themselves standardized through English and later international agreements rather than invented as a pressure unit from scratch.
It became the default pressure unit in US engineering as pound-force and inch-based measurement dominated American industry through the 19th and 20th centuries, and it remains in everyday use for tires and tools even as most other measurements in the US context stay imperial.
Historical origin. PSI was not the invention of a single named person; it developed through the process described above.
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
PSI — sources
- NIST Special Publication 811 — Guide for the Use of the International System of Units — Documents conversion factors for psi and other US customary pressure units.
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 psi?
1 psi equals 0.0680459639 atmospheres, using the exact defined conversion factor rather than an estimate.
How do I convert psi to atmosphere?
Multiply the psi value by 0.06804596391. The converter above does this instantly to whatever precision you set.
How do I convert atmosphere back to psi?
Use the reverse factor: 1 atmosphere equals 14.69594878 psi. You can also use the swap control in the converter above to flip the direction instantly.
What is a psi?
PSI (psi) measures pressure. PSI (pounds-force per square inch) equals exactly 6,894.757293168 pascals. It is classified as a US/imperial customary unit.
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 psi 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.
Where is the psi still used today?
United States (standard pressure unit for tires, tools, and plumbing)