Pressure converter
Convert between the pressure units you actually meet in the field — psi, bar, kPa, inches and feet of water, inches of mercury, atmospheres and kg/cm² — with psi and kPa shown for reference.
Pressure unit converter · everything via psi
everything converts through psi
What this does
This converts a pressure reading between twelve common units — psi, bar, kPa, MPa, Pa, inches of mercury (inHg), feet of water (ftH2O), metres of water (mH2O), millimetres of mercury (mmHg), torr, standard atmospheres (atm), and kg/cm². Every conversion is routed through a single anchor unit, pounds per square inch, so there is only one table of constants to trust and no tangle of direct unit-to-unit factors. A reference selector lets you show the result as a plain gauge conversion or shift it to absolute by adding one atmosphere.
The formula
Each unit is defined by how many psi one of it is worth. The value you type is first turned into psi, then psi is turned into the unit you want:
psi = value × factor[from], then result = psi ÷ factor[to].
The factors used here are: bar = 14.5038 psi, kPa = 0.145038 psi, MPa = 145.038 psi, Pa = 0.000145038 psi, inHg = 0.491154 psi, ftH2O = 0.433528 psi, mH2O = 1.42233 psi, mmHg = torr = 0.0193368 psi, atm = 14.6959 psi, and kg/cm² = 14.2233 psi. The psi and kPa equivalents are always shown beneath the answer as a quick cross-reference, because those are the two units most gauges and datasheets are labelled in.
Field note — gauge vs. absolute
A gauge reads zero at atmospheric pressure; an absolute scale reads about 14.70 psi (1 atm) there. Leave the reference on gauge for a straight unit conversion. Switch it to absolute and the tool adds 14.6959 psi to the psi-equivalent before converting, so 0 psig becomes 14.696 psia and 100 psig becomes 114.696 psia — the value the needle and green read-out then track. Watch inHg especially: it is used both for positive pressure and, on the vacuum side, for how far below atmospheric you are, so always confirm which reference a spec (psia vs psig, bara vs barg) is calling for.
Worked example
You have a European pump curve quoted in bar and a gauge on the skid reading psi. The curve says 6 bar at duty. In psi that is 6 × 14.5038 = 87.0 psi. Going the other way, a 100 psi relief setting is 100 ÷ 14.5038 = 6.895 bar, or 689.5 kPa — the two reference values the tool prints under every result. If the datasheet wanted that relief setting in bar absolute, flip the reference to absolute: (100 + 14.6959) ÷ 14.5038 = 7.908 bara.