20 psi to atm — 20 pounds per square inch in standard atmospheres
Exact 20 ÷ 14.695949 = 1.360919
20 pounds per square inch in other units
| Pascals | 137,895.15 | Pa |
|---|---|---|
| Hectopascals | 1,378.95 | hPa |
| Kilopascals | 137.895146 | kPa |
| Megapascals | 0.13789515 | MPa |
| Millibars | 1,378.95 | mbar |
| Bar | 1.378951 | bar |
| Standard atmospheres | 1.360919 | atm |
| Torr | 1,034.3 | Torr |
| Millimetres of mercury | 1,034.3 | mmHg |
| Inches of mercury | 40.720414 | inHg |
psi to atm at a glance
| Pounds per square inch | Standard atmospheres |
|---|---|
| 1 psi | 0.06804596 atm |
| 2 psi | 0.13609193 atm |
| 3 psi | 0.20413789 atm |
| 5 psi | 0.34022982 atm |
| 10 psi | 0.68045964 atm |
| 20 psi | 1.360919 atm |
| 25 psi | 1.701149 atm |
| 50 psi | 3.402298 atm |
| 100 psi | 6.804596 atm |
| 250 psi | 17.011491 atm |
| 500 psi | 34.022982 atm |
| 1,000 psi | 68.045964 atm |
How to convert pounds per square inch to standard atmospheres
Multiply by 0.06804596 — one pound per square inch is 0.06804596 standard atmospheres. That factor is exact: it comes from the definition of the units rather than from a measurement, so it will not change and does not need rounding.
Working 20 ÷ 14.695949 = 1.360919
In words: about one standard atmospheres.
What these units are
The pound per square inch and the standard atmosphere are covered in the pressure unit guide, along with every other unit on this page.
Questions
How many standard atmospheres are in a pound per square inch?
One pound per square inch is 0.06804596 standard atmospheres. This figure is exact — it comes from the definition of the unit, not a measurement.
What is 20 pounds per square inch in standard atmospheres?
20 pounds per square inch is 1.360919 standard atmospheres. The working is 20 ÷ 14.695949 = 1.360919.
What pressure should my tyres be?
Look at the sticker in the driver's door frame or the fuel flap, not the number moulded into the tyre — that one is the tyre's maximum, not the manufacturer's recommendation. Most cars sit somewhere around 32 to 35 psi, which is roughly 2.2 to 2.4 bar.
Is my tyre gauge measuring absolute or gauge pressure?
Gauge pressure — the amount above the surrounding air. A tyre reading 32 psi actually contains about 46.7 psi absolute, because atmospheric pressure of roughly 14.7 psi is already pressing on the other side of the gauge. Conversions on this page are between units, and leave that distinction alone.
Why do weather forecasts use hectopascals and millibars interchangeably?
Because they are the same size. One hectopascal is exactly one millibar, so the change from mbar to hPa was a relabelling rather than a conversion. Standard sea-level pressure is 1013.25 of either.
What is the difference between torr and mmHg?
Almost nothing, and the difference is deliberate. A torr is exactly one seven-hundred-and-sixtieth of a standard atmosphere; the conventional mmHg is defined as exactly 133.322387415 pascals. They diverge by about one part in seven million — invisible in medicine, occasionally not in vacuum work.