Pressure converter
Convert pascals, kilopascals, bar, standard atmospheres and pounds per square inch.
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How it works
Convert a pressure value between pascals, metric pressure multiples, psi, standard atmospheres and torr. Conversion changes units while preserving the original pressure reference: it does not change a gauge reading into an absolute reading.
A few things to know
The tool does not know whether input is gauge, absolute or differential pressure, and adds no atmospheric offset. Signed pressure differences are allowed; negative absolute pressure is not physically implied. Standard atmosphere is a unit, not measured local atmospheric pressure. Temperature-dependent liquid-column units are excluded. Display uses up to 12 significant digits; this is not arbitrary-precision arithmetic or a measurement calibration. Numeric magnitude is bounded to 1e100, with nonzero inputs at least 1e-100.
When to use this tool
A pressure conversion changes the unit, while a gauge-to-absolute conversion changes the reference point. This tool does the first task only. It translates a value among pascals, metric pressure multiples, psi, standard atmospheres and torr without adding an atmospheric offset. Signed values are accepted for differences or gauge readings, but the tool does not decide what reference the input uses. Keep that reference visible when using the result in an equipment specification, test record or separate calculation.
- Compare a pressure specification in bar with its psi equivalent while preserving the same reference.
- Translate a differential-pressure reading from kilopascals into pascals.
- Express a standard-atmosphere quantity in torr or metric pressure units for a documented calculation.
How to use pressure converter
Enter the pressure number
Use Value for the numeric reading only. Record whether it is gauge, absolute or differential in your own context because there is no reference selector.
Choose the pressure unit
Select From unit, such as bar, kPa or psi. Standard atmospheres use a defined unit factor rather than local measured air pressure.
Keep the reference when converting
Set To unit and calculate. Read Converted value and retain the original pressure reference when labeling it; the table and CSV provide other unit equivalents.
One bar expressed in psi
Inputs
Value 1; From unit Bar; To unit Pounds-force per square inch (psi).
Result
Converted value is 14.503773773 psi. The table also gives 100 kilopascals and 100,000 pascals.
What it means
If the original value was 1 bar gauge, the result is 14.503773773 psi gauge. It has not become an absolute pressure, because no ambient-pressure offset has been added.
Common mistakes to avoid
Changing reference accidentally
Keep gauge, absolute or differential labeling consistent. Changing units alone cannot supply an absolute pressure from a gauge reading.
Equating bar and atmosphere
A bar is 100,000 Pa, while a standard atmosphere is 101,325 Pa. Their close values do not make them identical.
Assuming a liquid-column definition
Millimeters of mercury and water-column units can have convention or temperature distinctions. They are excluded rather than silently equated to another unit.
Frequently asked questions
Definitions, edge cases, and practical next steps for this tool. Search all tool FAQs ↗
How are pressure units converted?
The input is multiplied by its source unit’s pascal factor and divided by the target factor. This is a proportional conversion. No atmospheric offset, temperature assumption or change of gauge, absolute or differential reference is part of the calculation.
Can this convert gauge pressure to absolute pressure?
No. That task needs the appropriate reference pressure in addition to the reading. The converter preserves the basis of the supplied value, so gauge units remain gauge units. It cannot infer local atmospheric pressure or establish the original instrument’s reference.
What does the standard atmosphere option mean?
It is the defined unit atm, equal to 101,325 pascals. It is not a live measurement of air pressure at your location. Weather and altitude are not inputs, and the converter does not estimate their effect on an actual ambient reading.
Are millibars and hectopascals equivalent?
Yes. Each is 100 pascals, so their numerical values match for the same pressure and reference. The different names arise from the unit and prefix convention; no offset is involved when converting mbar to hPa.
What definition of psi is used?
Psi means pounds-force per square inch. The factor uses the international avoirdupois pound, standard gravity and the international inch. It does not turn mass pounds into a local weight measurement or use a location-specific gravitational acceleration.
Are torr and millimeters of mercury identical here?
The listed Torr option means one-seven-hundred-sixtieth of a standard atmosphere. There is no millimeter-of-mercury option. Do not relabel an arbitrary mercury-column reading as torr without checking the measurement convention and precision needed by your source.
Why are negative values accepted?
A pressure difference or a gauge value can be signed relative to a reference. The tool preserves that sign during unit conversion. Accepting a negative number does not establish that a negative absolute pressure is physically meaningful or validate an instrument reading.
Can I use the result as an equipment setting?
Confirm the equipment’s unit, pressure reference, operating range and instructions before using a number. The converter provides arithmetic equivalents only and does not check equipment suitability or calibrate a gauge. Output precision should reflect the original specification or measurement.
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Sources and method
Use the references below to check definitions and platform guidance. The model’s scope and limits are explained above. Read our editorial standards.