ATM to PSI Converter
Type atmospheres to get psi. One standard atmosphere, the average air pressure at sea level, is 14.696 psi.
1 atm =
14.6959psi
1 standard atmosphere is 14.6959 pounds per square inch.
- 1 atm
- 14.6959 psi
- 1 psi
- 0.06805 atm
How to convert atm to psi
Multiply the number of atmospheres by 14.6959. A standard atmosphere is fixed at exactly 101,325 pascals, the average air pressure at sea level, and that divided by 6,894.757 pascals per psi is 14.6959488, rounded here to 14.6959.
At 3 atm, a common figure in gas-law homework: 3 × 14.6959 = 44.09 psi absolute. Atmospheres are almost always absolute pressures, so the psi result is too (psia).
Watch for the older technical atmosphere (at), defined as one kilogram-force per square centimeter. It is 98,066.5 Pa, or 14.2233 psi, about 3% less than the standard atmosphere, and still turns up in older engineering tables.
pounds per square inch = standard atmospheres × 14.6959 (rounded)
- The standard atmosphere is defined as exactly 101,325 Pa, which is 1.01325 bar or 14.695 95 psi. Source: NIST SP 811, Appendix B.8: conversion factors by unit.
How to estimate atm to psi in your head
Call one atmosphere 14.7 psi, or 15 for a rough figure. Divers use a neat rule: every 10 meters (33 feet) of seawater adds about one atmosphere, so at 20 m you breathe air at about 3 atm absolute, roughly 44 psi.
Atmospheres to psi table
Half an atmosphere up to a hundred, in pounds per square inch absolute.
| Standard atmospheres (atm) | Pounds per square inch (psi) | Example |
|---|---|---|
| 0.5 | 7.348 | air pressure near 5,500 m altitude |
| 1 | 14.6959 | sea level |
| 1.5 | 22.0439 | |
| 2 | 29.3919 | about 10 m under the sea |
| 2.5 | 36.7399 | |
| 3 | 44.0878 | |
| 4 | 58.7838 | about 30 m under the sea |
| 5 | 73.4797 | |
| 6 | 88.1757 | |
| 7 | 102.872 |
Show all 14 rowsShow fewer
| 10 | 146.959 | |
| 20 | 293.919 | |
| 50 | 734.797 | |
| 100 | 1,469.59 |
Frequently Asked Questions
How many psi is 1 atm?
1 atm is 14.696 psi, usually rounded to 14.7. It is an absolute pressure: the full weight of the air above you at sea level.
How many psi is 2 atm?
2 atm is 29.39 psi absolute. Subtract the 14.70 psi of the air around you and a gauge would read 14.70 psi, exactly one atmosphere over.
What is the difference between atm and bar?
They are close but not equal. 1 atm is 101,325 Pa and 1 bar is 100,000 Pa, so an atmosphere is about 1.3% bigger. In psi that is 14.70 against 14.50.
Why does a tire gauge read 0 at 1 atm?
Tire gauges measure gauge pressure, which ignores the atmosphere that is already pushing on both sides. A tire at 32 psi on the gauge is at about 46.7 psi absolute, or 3.2 atm.