Convert PSI to Atmospheres
PSI to atmospheres is the conversion you need when a pressure reading is in the everyday US unit — pounds per square inch — but you want it in atmospheres, the unit that measures pressure against sea-level air. One psi is approximately 0.06804596390987773 atm, and since sea-level air pressure is about 14.7 psi, that's the same as 1 atmosphere.
Pounds per square inch to Atmospheres conversion table
| Pounds per square inch (psi) | Atmospheres (atm) |
|---|---|
| 1 | 0.068046 |
| 2 | 0.136092 |
| 3 | 0.204138 |
| 5 | 0.34023 |
| 10 | 0.68046 |
| 20 | 1.360919 |
| 50 | 3.402298 |
| 100 | 6.804596 |
| 500 | 34.022982 |
| 1,000 | 68.045964 |
The formula
To convert psi to atmospheres, multiply the pressure in psi by 0.06804596390987773:
atmospheres = psi × 0.06804596390987773
A worked example
Say you want to check that sea-level air pressure, about 14.696 psi, really is one atmosphere:
14.696 × 0.06804596390987773 = 1.0000035 atm
So 14.696 psi is about one atmosphere — the air pressure you're standing in at sea level.
Why it's an approximation
Psi (pounds per square inch) is a US imperial unit, built from the pound and the inch. The standard atmosphere is defined from metric pressure units. The two don't divide evenly, so converting between them lands on a long, non-terminating number — 0.06804596390987773 is that value rounded off. It's carried to enough decimals for any everyday job, but it stays an approximation rather than a clean, exact figure.
When you'll use it
Comparing a tire, tank, or gauge reading in psi against atmospheric pressure, or working a chemistry or physics problem where pressures are counted in atmospheres.
Frequently asked questions
How many atmospheres are in one psi?
About 0.06804596390987773 atmospheres. It's a rounded figure — psi is an imperial unit that doesn't line up evenly with the atmosphere, so this factor is carried to enough decimals to be practical but is not exact.
How many psi is one atmosphere?
About 14.7 psi. Sea-level air pressure is defined as one standard atmosphere, and 14.696 psi works out to roughly 1.0000035 atm — so give or take rounding, 14.7 psi is one atmosphere.
Is the psi to atmospheres conversion exact?
No. Psi is a US imperial unit, and its conversion to the standard atmosphere is a long, non-terminating number. The factor 0.06804596390987773 is rounded — more decimal places give more precision if you need it.