Pressure Unit Converter

Enter a pressure in either field, choose the source and target units, and the other value updates immediately. Swap reverses the conversion.

Use Pressure reference only when it matters whether the supplied reading is absolute, gauge, or differential. The reference label does not change the numerical unit conversion.

The pascal, symbol Pa, is the SI derived unit of pressure. One pascal equals one newton of force distributed over one square metre: 1 Pa = 1 N/m².

A pascal is small for many everyday engineering pressures, so kilopascals and megapascals are commonly used. One kPa equals 1,000 Pa and one MPa equals 1,000,000 Pa.

Pressure measures force per unit area. It is different from force itself, even though the pascal is defined using the newton.

One pound per square inch is approximately 6.894757 kilopascals.

To convert psi to kPa, multiply by approximately 6.894757. For example, 20 psi is about 137.8951 kPa and 32 psi is about 220.6322 kPa.

PSI is common in tyre, pneumatic, hydraulic, compressed-air, and US engineering specifications, while kPa is widely used in metric systems.

To convert kilopascals to psi, divide by approximately 6.894757.

For example, 20 kPa is approximately 2.900755 psi and 100 kPa is approximately 14.5038 psi.

The standard atmosphere, symbol atm, is a defined reference pressure equal to exactly 101,325 pascals.

Therefore 2.5 atm equals exactly 253,312.5 Pa. One pascal is approximately 0.00000986923 atm.

A standard atmosphere is a fixed reference value. It is not a statement that the actual outdoor atmospheric pressure at a particular place and time is exactly one atmosphere.

One bar equals exactly 100,000 Pa, which is also exactly 100 kPa.

One millibar equals exactly 100 Pa. One hectopascal also equals exactly 100 Pa, so 1 mbar = 1 hPa numerically.

This equivalence is why weather reports may use hPa or mbar for atmospheric pressure without changing the numerical value.

One megapascal equals approximately 145.0377 psi.

Megapascals are commonly used for higher pressures and material-related measurements because 1 MPa equals one million pascals.

For example, 2 MPa is approximately 290.0755 psi or 19.7385 standard atmospheres.

One kilogram-force per square centimetre equals exactly 98,066.5 Pa using standard gravity. One psi is therefore approximately 0.07030696 kgf/cm².

The formal force-per-area notation is kgf/cm². Informal engineering documents and searches may shorten this to kg/cm², even though kilogram is a mass unit rather than a force unit.

For pressure conversion, this calculator interprets the supported kgf/cm² unit using the kilogram-force definition.

The final g in psig, barg, or kgf/cm²g indicates gauge pressure: the reading is referenced to atmospheric pressure rather than to a perfect vacuum.

The g does not create a different psi, bar, or kgf/cm² unit conversion factor. For example, 1 psig has the same pressure interval as 1 psi, so converting a gauge reading from psi to kgf/cm² uses the ordinary pressure-unit factor.

Converting between gauge and absolute pressure is different. That requires the atmospheric reference pressure: absolute pressure equals gauge pressure plus the applicable atmospheric pressure.

Absolute pressure is referenced to a perfect vacuum. Gauge pressure is referenced to atmospheric pressure. Differential pressure compares one pressure point with another.

These references describe what zero means for the measurement; they do not change the size of a pascal, psi, bar, or other pressure unit.

The converter lets you label the reference so a negative gauge or differential value is not incorrectly rejected as though it were an absolute pressure.

Using the conventional mmHg factor in this converter, 120 mmHg is approximately 2.320413 psi.

The same pressure is approximately 15,998.6865 Pa, 15.9987 kPa, 0.1599869 bar, or 0.157895 atm.

Millimetres of mercury are widely encountered in medical and manometric measurements, but converting the unit does not interpret the meaning of a blood-pressure reading.

One Torr is defined as exactly 1/760 of a standard atmosphere.

Conventional mmHg is based on a conventional mercury-column definition. Its conversion factor is extremely close to one Torr, which is why the two values are often treated as equivalent for ordinary work.

For precision-sensitive work, the unit definition matters. The converter therefore keeps Torr and conventional mmHg as separate choices rather than forcing them to be exactly equal.

A micron of mercury, written here as µmHg, is one-thousandth of a conventional millimetre of mercury.

This unit is used in vacuum work because pressures can be far below atmospheric pressure. For example, 500 µmHg equals 0.5 mmHg and approximately 0.019685 inHg.

Vacuum readings can also be expressed in Torr, pascals, mbar, or other units. Always check whether an instrument reports absolute pressure or a gauge-style vacuum reading before comparing measurements.

Inches of mercury, symbol inHg, are used in weather reporting, aviation altimeter settings, and vacuum measurements.

One conventional inHg is approximately 3,386.38864 Pa, or about 3.38639 kPa.

As with mmHg, a mercury-column unit should be interpreted using the definition associated with the source measurement when precision matters.

The table collects several pressure conversions that commonly appear in engineering, atmospheric, laboratory, vacuum, and educational work.

The live converter uses the full stored unit factors before formatting the displayed result.

Pressure can be expressed using many units because different industries developed around different measurement systems and practical ranges.

The converter uses the pascal as the common reference so conversions do not need to chain through rounded intermediate values.

Converting 100 psig to bar produces a bar value describing the same gauge pressure. It does not silently turn that value into absolute bar.

Likewise, converting an absolute pressure between psi, kPa, bar, or atm keeps it absolute. Unit conversion changes the numerical scale, not the physical reference.

If you need to convert gauge pressure to absolute pressure, the atmospheric reference must be known or explicitly assumed.

An exact unit definition does not make the original pressure measurement exact.

Instrument accuracy, calibration, resolution, temperature effects, pressure reference, installation, and measurement procedure can matter more than the conversion mathematics.

The converter preserves useful significant digits for small pressure values and uses scientific notation when a fixed decimal display would be impractical.