Pressure units are a mess of overlapping traditions — metric bar, American PSI, the SI pascal, and the atmosphere everyone learned in school — and most converters quietly round one of them. Our new Pressure Converter doesn’t: PSI and the standard atmosphere are legal definitions, not measurements, and this tool uses their exact defining constants.
- Five units, one base — pascals (Pa), kilopascals (kPa), bar, PSI, and atmospheres (atm), all defined through pascals so nothing drifts from stacking approximations.
- Exact constants — 1 psi is defined as exactly 6894.757293168 Pa and 1 atm as exactly 101,325 Pa; this tool uses those figures, not rounded textbook shortcuts.
- Type in either direction — edit the “From” field or the “Result” field directly and the other side updates live, so you’re never stuck guessing which box is the input.
- Swap in one click — flip the two units instantly when you realize you set them up backwards.
- All five units at once — a reference table shows your value converted into every unit simultaneously, not just the pair you picked.
A good sanity check: standard sea-level atmospheric pressure, 1 atmosphere, comes out to 101,325 Pa, 101.325 kPa, about 1.01325 bar, and about 14.6959 psi — numbers you can check against any reference table you trust. Enter your tire’s PSI rating instead and read the bar or kPa column straight off.