ATM to PSI Converter
Pick a common pressure to convert, or enter your own value.
One standard atmosphere (atm) is defined as 101 325 pascals, the pressure exerted by the air column at sea level on an average day. Converting it to psi — the unit American engineers, tire shops and dive planners use — means multiplying by 14.6959. This converter runs the calculation both ways so you can take a lab datasheet quoted in atm and give a mechanic a number in psi, or vice versa.
How the conversion works
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1
Enter a value in atm or psi
Either field accepts any positive decimal.
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2
The other field updates instantly
Using the exact relation 1 atm = 14.69594877551 psi.
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3
Read the converted number
Rounded to four decimals by default; toggle more precision if you need it for calibration work.
Exact conversion factor
1 atm = 101 325 Pa
1 psi = 6 894.757 293 168 Pa
1 atm = 101 325 / 6 894.757... = 14.695 948 775 5... psi
The standard atmosphere is defined exactly as 101 325 Pa by ISO 2533. The pound-force per square inch derives from the pound-force (4.448 222 N) and inch (0.0254 m), so 1 psi equals 4.448222 / 0.0254² pascals.
Common reference points
| What | Pressure in atm | Pressure in psi |
|---|---|---|
| Sea-level atmospheric pressure | 1.000 | 14.70 |
| Car tire (passenger, cold) | 2.1 - 2.3 | 30 - 34 |
| Bicycle road tire | 6.8 - 8.2 | 100 - 120 |
| Scuba tank full (232 bar) | 229 | 3365 |
| Espresso extraction | 9.0 | 132 |
| Mariana Trench hydrostatic | 1086 | 15 967 |
Related pressure units
- bar — 100 000 Pa exactly. 1 bar ≈ 0.987 atm ≈ 14.504 psi. Weather forecasts in Europe often use millibars (1 mbar = 100 Pa).
- kPa — Kilopascal, SI. 1 atm = 101.325 kPa.
- mmHg / torr — Millimetres of mercury. 1 atm = 760 mmHg exactly by definition.
- inHg — Inches of mercury, still standard in US aviation altimeters. 1 atm = 29.92 inHg.
Watch for “gauge” vs “absolute”
Tire pressure gauges read psig — pressure above ambient. Your tire at “32 psi” is at 32 psig, which is 46.7 psi absolute. When converting to atm, be clear which you mean: 1 atm gauge (2 atm absolute) is not the same as 1 atm absolute.
Frequently Asked Questions
Almost, but not exactly. 1 bar = 100 000 Pa; 1 atm = 101 325 Pa. The difference is about 1.3%, often ignored in rough work but real enough to matter in calibration and scientific contexts.
A car tire at 32 psi is carrying about 2.18 atm gauge, or more than three atmospheres absolute — a lot of force over every square inch. It is a genuinely large pressure, just expressed in small units.
Yes, roughly. The “standard atmosphere” is a sea-level reference on an average day. At higher altitudes or low-pressure weather, you experience slightly less; 1 atm is a rounded textbook value.
In SI-native industries (science, European engineering): pascal or kilopascal. In mechanical and automotive contexts in the US: psi. In meteorology: hPa (hectopascal = mbar). Atm shows up mostly in chemistry and dive tables.
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