Tyre pressures
Tyre pressures are given in psi in the US and the UK and in bar or kPa across much of Europe. 32 psi is 2.21 bar or 220.63 kPa, and 2.5 bar is 36.26 psi. The figure on the door sticker and the one on a tyre gauge are both measured above the air around them, and convert the same way.
Atmospheres and mercury
One standard atmosphere is 101,325 Pa: 1.01325 bar, 14.70 psi and about 760 mmHg. 1 bar is 100,000 Pa, a little less than an atmosphere. Blood pressure is given in mmHg, so a reading of 120/80 is 16.0 over 10.7 kPa.
Questions
What is the difference between psig and psia?
psig is gauge pressure, measured above the air around it; psia is absolute, measured from a vacuum. At sea level psia is about 14.7 more than psig. The converter changes units only, so a gauge reading stays a gauge reading.
Is mmHg the same as torr?
Nearly. A torr is exactly 1/760 of an atmosphere; the millimetre of mercury here is 133.322387415 Pa, about 0.000014% more. The difference is far below what a blood pressure cuff can show.