PSI to Atm Converter
Neither unit is defined in terms of the other: a standard atmosphere is fixed at exactly 101,325 pascals, while a pound per square inch works out at 6,894.757293168 pascals from the exact definitions of the pound, standard gravity and the inch. Dividing one by the other is where 14.6959487755 psi per atmosphere comes from, so psi to atm is a division by that figure, or a multiplication by 0.0680459639099, with no round number anywhere in it. That makes 1 psi 0.0680459639099 atm, 10 psi 0.680459639099 atm, 32 psi 2.17747084512 atm and 100 psi 6.80459639099 atm. The familiar 14.7 psi is a rounded stand-in for that ratio: type it here and the answer reads 1.00027566948 atm, about 0.028 percent over one atmosphere. This page opens the converter with psi in the From box and atmospheres in the To box, ahead of whatever pair you converted last, and the list under the answer carries the same pressure in pascals, kilopascals and bar, with millimetres of mercury behind the uncommon units switch. It changes units and nothing else: whether a psi reading was taken against a vacuum or against the air around the gauge is something only you can know.
1 psi in every pressure unit
Common questions
- How many atm is 1 psi?
- 0.0680459639099 atm, which is 6,894.757293168 / 101,325. It scales straight up, since nothing about this pair is affine: 2 psi is 0.13609192782 atm, 5 psi is 0.340229819549 atm, 10 psi is 0.680459639099 atm, 20 psi is 1.3609192782 atm, 50 psi is 3.40229819549 atm and 100 psi is 6.80459639099 atm. The headline updates as you type, and Copy result puts the plain number on the clipboard without the thousands separators shown on screen.
- What is the formula for psi to atm?
- Atmospheres = psi / 14.6959487755, or psi × 0.0680459639099 if you would rather multiply. Going back the other way, psi = atm × 14.6959487755, so 0.5 atm is 7.34797438776 psi, 2 atm is 29.391897551 psi and 3 atm is 44.0878463265 psi. The Swap units button between the two boxes reverses the pair, which turns this page into an atm to psi converter without a reload.
- Is 14.7 psi one atmosphere?
- Close, and not exact. Type 14.7 and the answer reads 1.00027566948 atm, about 0.028 percent over. One standard atmosphere is 14.6959487755 psi as printed here, because the atmosphere is defined as exactly 101,325 pascals and the psi is not a neat fraction of it. Rounding to 14.7 costs a few thousandths of an atmosphere, which disappears in tyre and compressor work and shows up the moment you multiply it by a few hundred.
- My tyre gauge reads 32 psi. Is that 2.17747084512 atm of pressure in the tyre?
- It is 32 psi above the air around the gauge, which the converter reports as 2.17747084512 atm, and stated absolutely the same tyre is one atmosphere higher. That addition is unusually easy to see in this pair: 32 psi absolute would be written 46.6959487755 psi, which converts to 3.17747084512 atm, the same digits with the 2 turned into a 3. The converter never adds or removes that atmosphere for you, so decide whether your figure is gauge (psig) or absolute (psia) before you convert it.
- What is 2,000 psi in atmospheres?
- 136.09192782 atm. High-pressure figures follow the same single factor, so 200 psi is 13.609192782 atm, 500 psi is 34.0229819549 atm and 3,000 psi is 204.13789173 atm, while a household water supply at 60 psi is only 4.08275783459 atm. Answers stay in plain decimal with thousands separators until they reach a quadrillion, so nothing in this range turns into exponential notation.
- Which other pressure units does it show at the same time?
- Every one in the category except the unit you typed in, worked out at once rather than one target at a time. For 1 psi the list under the answer reads 6,894.75729317 Pa, 6.89475729317 kPa, 0.0689475729317 bar and 0.0680459639099 atm, with 51.7149252039 mmHg appearing once you turn on the uncommon units switch in the readout strip, labelled Show 1 more. Notice how bar and atm sit 1.3 percent apart: 100 psi is 6.89475729317 bar but 6.80459639099 atm.
- Why does 14.6959487755 psi come back as 0.999999999999 atm rather than 1?
- Because the figure you typed is itself a rounded version of a decimal that never ends, and results print to twelve significant digits, so the shortfall lands in the last place instead of being hidden. Nothing is wrong with the arithmetic: press Swap units, type 1 with atm in the From box, and the answer comes back as exactly 14.6959487755 psi. Anything that is not a number leaves the headline reading Ready and prints a line under the stage saying what a number here looks like, and a comma is read as a thousands separator, so 1,234.5 is accepted as 1234.5.
- Will the main unit converter remember psi and atm afterwards?
- No, and that is deliberate. This page sets psi and atm on arrival, ahead of whatever pair the converter last remembered, and it leaves that memory untouched: go back to /unit-converter and it is still on the units you left it on. The number you last typed does travel with you, along with the uncommon units switch, since that is usually the figure you are still working on.
Conversion factors are the exact legal definitions where one exists. An inch is exactly 2.54 cm and a pound exactly 0.45359237 kg, so those conversions are exact rather than approximate. Temperature uses offsets rather than factors, and that is shown in the working.