Pressure Unit Converter
| Unit | Symbol | = base units |
|---|---|---|
| pascal | Pa | 1 Pa |
| kilopascal | kPa | 1,000 Pa |
| megapascal | MPa | 1,000,000 Pa |
| bar | bar | 100,000 Pa |
| pound per square inch | psi | 6,894.757293168 Pa |
| standard atmosphere | atm | 101,325 Pa |
| millimeter of mercury | mmHg | 133.322387415 Pa |
| kgf per square centimeter | kgf/cm² | 98,066.5 Pa |
| hectopascal | hPa | 100 Pa |
| torr | Torr | 133.322368421 Pa |
| inch of mercury | inHg | 3,386.389 Pa |
| millimeter of water | mmH₂O | 9.80665 Pa |
How to Use
Overview
Pressure is hard because of gauge versus absolute readings and because every trade writes the same pressure differently: tyres in psi, weather in hPa, vacuum pumps in torr, hydraulics in MPa, boiler plates in kgf/cm², blood pressure in mmHg. This converter is built on the pascal and lists twelve units, with one standard atmosphere equal to 101,325 Pa, 760 mmHg and 760 torr, so the scattered coefficients no longer have to be memorised. On a low-pressure line two percent is noise, on a high-pressure vessel it is not, and the nameplate unit always wins over verbal habit. Field work adds a second layer the table cannot remove: most dial gauges show pressure above ambient, while datasheets quote absolute pressure, and the gap between them is the local barometric reading. A vessel tested at ten bar on a gauge is at roughly eleven bar absolute at sea level, which matters when a relief valve is rated in absolute terms. Aviation adds its own habit of quoting inches of mercury for altimeter settings, while weather services use hectopascals for the same quantity. Vacuum work prefers torr and millibar while a mercury column is still the reference in older laboratories, and none of these coincide exactly with the pascal. A tyre gauge reading is therefore always relative to the weather of the day.
Features
- Twelve units in one view: Pa, kPa, MPa, hPa, bar, psi, atm, mmHg, torr, inHg, mmH2O, kgf/cm2
- The atmosphere trio lines up: 1 atm = 101,325 Pa = 760 mmHg = 760 torr
- bar and psi side by side for engineering: 1 bar is about 14.5038 psi
- MPa and kgf/cm2 cover hydraulics and boilers, with 1 kgf/cm2 = 98,066.5 Pa
- Vacuum and draft work with torr, inHg and mmH2O on their own factors
- Expression input and batch conversion, zero to eight decimals, exported as TXT or CSV
How to use
- Enter a pressure figure or expression, for example 2.5 or 1+1
- Pick the source unit: psi for tyres, MPa for hydraulics, hPa for weather, torr for vacuum
- Leave the target empty to see all twelve results, or pin one such as bar
- Read atm against bar carefully, they differ by about 1.3 percent and are not interchangeable
- Paste several lines and export TXT or CSV for an equipment register or inspection record
Notes
- Twelve pressure units cover pascal, kilopascal, megapascal, bar, psi, atmosphere, mmHg, kgf/cm², hectopascal, torr, inHg and mmH2O, with the pascal as the base and no change to gauge or absolute meaning.
- One atmosphere is 101,325 Pa or 760 mmHg or 760 torr, while one bar is 100,000 Pa, about 1.3 percent apart, so bar and atm cannot be swapped on a vessel nameplate.
- psi is pounds-force per square inch at 6,894.757293168 Pa and kgf/cm² is 98,066.5 Pa, about two percent from bar, so hydraulic and pneumatic labels use two systems side by side.
- inHg is 3,386.389 Pa, mmH2O is 9.80665 Pa and hPa equals mbar; gauge and absolute pressure differ by one atmosphere, so mixing them shifts results by 101,325 Pa.
- Altitude and temperature effects on a sensor reading are not corrected here; CSV exports numbers and units must be unified before comparison.
- psi is pounds-force per square inch: 6,894.757293168 Pa, so a 32 psi tyre is roughly 2.2 bar
- mmHg and torr are numerically near-identical at 133.322368421 Pa, though torr is defined by ideal gas and mmHg by mercury height
- One atmosphere is defined as exactly 101,325 Pa; spoken engineering shorthand may mean bar or kgf/cm2, so read the context