Pressure Converter

About this tool

Pressure values appear across very different scales and unit systems depending on the field — a tire shop uses psi, a lab uses atmospheres or torr, and engineering datasheets use bar or kilopascals. This pressure converter covers six common units: pascal (Pa), kilopascal (kPa), bar, pound per square inch (psi), standard atmosphere (atm) and torr. Enter a value, choose the From and To units, and the converted result appears instantly, shown to twelve significant digits. Every unit is converted through pascals using defined factors — 1 bar = 100,000 Pa, 1 atm = 101,325 Pa, 1 torr = 101,325 ⁄ 760 Pa, and 1 psi = 6,894.757293168 Pa — so round trips stay consistent. For hectopascals, use kPa and multiply by 10; for mmHg, torr is equal to within a fraction of a part per million. Everything runs locally in your browser.

Why use it

• Six Essential Units: Covers Pa, kPa, bar, psi, atm and torr — the units used on tire gauges, compressor specs, lab equipment and vacuum datasheets.

• Live Conversion: The result updates on every keystroke or unit change — no submit button, no page reload.

• Defined Conversion Factors: Bar, atm and torr use their exact definitions in pascals, and psi uses the full 6,894.757293168 Pa factor rather than a rounded 6,895.

• Twelve Significant Digits: Results keep up to twelve significant digits, enough for engineering datasheets and lab reports, with scientific notation for extreme values.

• Offline Capable: All conversion factors are built into plain browser JavaScript. No API call is needed, so the tool works anywhere connectivity is unreliable.

How to use

1. Type the pressure in the Value field
2. Choose the unit you are converting from in the From dropdown
3. Choose the target unit in the To dropdown (it starts on kPa)
4. Read the converted value and the From → To label, which update as you type

When it helps

• Checking tire pressure when a car's manual lists psi but your gauge reads kPa or bar.
• Converting a hydraulic or pneumatic system spec from bar to psi for a US-manufactured part.
• Comparing a weather reading in kPa with the standard atmosphere value.
• Converting a vacuum reading in torr to pascals for a physics or chemistry assignment.
• Verifying an autoclave or compressor spec that mixes bar and psi in different sections of a manual.

Examples

Tips

• 1 atm ≈ 1.01325 bar ≈ 14.7 psi — close enough for estimates, but not the same; never use them interchangeably in precision specs.
• Tire shops post psi in the US and kPa in metric countries; your car's door sticker has both values and is the authoritative source.
• mmHg and torr are effectively identical for every practical application — the difference is sub-ppm.
• Gauge pressure = absolute pressure minus 1 atm — always clarify which type a specification is using before converting.
• Engineering specs typically express pressure in Pa, kPa, MPa, or bar — never mix units within a single document without converting explicitly.

Frequently Asked Questions

Glossary

Pascal (Pa)

The SI derived unit of pressure, defined as one Newton per square metre. Most scientific and engineering standards express pressure in Pascals or multiples thereof (kPa, MPa). Standard sea-level atmospheric pressure is 101,325 Pa.

Bar

A non-SI metric unit of pressure equal to exactly 100,000 Pa. Widely used in European industry, meteorology (millibar = hPa), and hydraulics. 1 bar is approximately equal to one standard atmosphere.

Pound per Square Inch (psi)

A US customary unit of pressure equal to one pound-force applied to an area of one square inch. Commonly used for tire inflation, hydraulic systems, and HVAC equipment in the United States.

Atmosphere (atm)

A unit of pressure defined as exactly 101,325 Pa, representing the average sea-level atmospheric pressure. Used as a reference standard in chemistry and physics, and as a rough rule-of-thumb in diving depth calculations.

Millimetre of Mercury (mmHg)

A pressure unit defined as the pressure exerted by a 1 mm column of mercury at 0 °C under standard gravity. Widely used in medicine for blood pressure readings and in meteorology for barometric pressure.

Torr

A unit of pressure equal to 1/760 of a standard atmosphere (approximately 133.322 Pa), nearly identical to 1 mmHg. Commonly used in vacuum engineering and low-pressure physics experiments.