Convert Atmospheres to PSI
Atmospheres to psi is the conversion you need when a pressure is quoted in atmospheres but your gauge reads in pounds per square inch. One standard atmosphere is approximately 14.696 psi — the familiar 'about 14.7 psi at sea level' — so the psi number always comes out much larger.
Atmospheres to Pounds per square inch conversion table
| Atmospheres (atm) | Pounds per square inch (psi) |
|---|---|
| 1 | 14.695949 |
| 2 | 29.391898 |
| 3 | 44.087846 |
| 5 | 73.479744 |
| 10 | 146.959488 |
| 20 | 293.918976 |
| 50 | 734.797439 |
| 100 | 1,469.594878 |
| 500 | 7,347.974388 |
| 1,000 | 14,695.948776 |
The formula
To convert atmospheres to psi, multiply the number of atmospheres by 14.696:
psi = atmospheres × 14.696
A worked example
Say a reading is 2 atmospheres and you want it in psi:
2 × 14.696 = 29.392 psi
So 2 atmospheres is about 29.392 psi.
Why it's an approximation
The "atmosphere" here is the standard atmosphere (atm), defined exactly as 101,325 pascals — an exact metric value. But psi (pounds per square inch) is an imperial unit built from the pound and the inch, and those don't divide evenly into the metric definition. Worked out in full, one atmosphere is 14.69594877551345 psi, which is why the everyday factor 14.696 (often rounded further to 14.7) is an approximation rather than an exact number.
When you'll use it
Matching a pressure quoted in atmospheres to a gauge that reads in psi — tire pressure, air compressors, and US-market equipment where psi is the standard unit and the atmosphere shows up in science or reference figures.
Frequently asked questions
How many psi are in one atmosphere?
About 14.696 psi. This is the '14.7 psi at sea level' figure people quote. It's a rounded value because psi is an imperial unit that doesn't divide evenly into the atmosphere's exact metric definition.
Why is sea-level pressure called 14.7 psi?
Because one standard atmosphere — roughly average air pressure at sea level — works out to about 14.696 psi, which most people round to 14.7 for everyday use.
Is the atmospheres to psi conversion exact?
No. The atmosphere is defined in exact metric terms (101,325 pascals), but psi is imperial, so the two don't divide evenly. The factor 14.696 is rounded for everyday use, and more decimal places give more precision if you need it.