Pa to psi Converter
The Pa to psi converter changes pressure from pascals into pounds per square inch and shows the same input in kPa, bar, and atm. It is designed for the everyday friction between SI pressure data and equipment labeled in psi: sensors, compressors, pumps, tires, HVAC static pressure, hydraulics, and imported machinery. The page follows the calculator’s implemented factor exactly, so the examples here match what the form displays.
A pascal is the SI pressure unit equal to one newton per square meter. It is small compared with common mechanical pressures, which is why standard atmospheric pressure is 101,325 Pa and a typical car-tire pressure is hundreds of thousands of pascals. Psi expresses pounds-force over square inches. It remains common in the United States and in many mechanical trades, even when the engineering model behind the equipment uses SI units.
The calculator accepts nonnegative pascal values. It does not ask whether the pressure is gauge, absolute, or differential because that distinction is not part of the unit conversion. If a pressure starts as absolute Pa, the psi result is absolute psi. If it starts as gauge Pa, the psi result is gauge psi. For an explicit gauge-to-absolute pressure shift, use the PSIG to PSIA converter.
Formula
The form’s forward conversion is:
The reciprocal shown in the note comes from the same stored factor:
The support rows are calculated from the original pascal input:
The psi factor is rounded in this converter. That means the reciprocal displayed by the calculator is about 6,894.745 Pa per psi, while high-precision references often give a slightly different value. The difference is small for typical field conversions, but it is worth noting for metrology work.
Example
Suppose a pressure specification lists 200,000 Pa. The calculator multiplies by its psi factor:
The primary result is 29.007548 psi. The supporting rows are:
so the kPa row is 200 kPa. The bar row is:
so it displays 2 bar. The atmosphere row is:
so it displays 1.973847 atm. The calculator note also says one psi is about 6,894.745 Pa, matching the reciprocal of 0.000145038.
Reference table
| Pascals | psi using calculator factor | kPa | bar | atm |
|---|---|---|---|---|
| 1 Pa | 0.000145 psi | 0.001 kPa | 0.00001 bar | 0.00001 atm |
| 1,000 Pa | 0.145038 psi | 1 kPa | 0.01 bar | 0.009869 atm |
| 10,000 Pa | 1.45038 psi | 10 kPa | 0.1 bar | 0.098692 atm |
| 101,325 Pa | 14.695949 psi | 101.325 kPa | 1.01325 bar | 1 atm |
| 200,000 Pa | 29.007548 psi | 200 kPa | 2 bar | 1.973847 atm |
| 500,000 Pa | 72.519 psi | 500 kPa | 5 bar | 4.934616 atm |
Where Pa to psi matters
Engineering software and scientific sensors often output pascals because Pa fits neatly with SI force and area. Maintenance instructions, gauges, and product labels may still use psi. A pump curve might list Pa in the model but psi at the gauge port. A tire placard outside the United States may list kPa, while a handheld tire gauge reads psi. Converting carefully helps you compare the actual pressure rather than guessing from a rough mental conversion.
Weather and building systems can involve small pressure differences. Fan static pressure, room pressurization, and duct measurements may be in pascals or inches of water, while some field tools show psi. In these small ranges, an extra zero matters. A value of 500 Pa is only 0.072519 psi, so mistaking Pa for kPa would be a thousandfold error.
For related pages, use the pressure converter when you need many units, bar to psi for the 100,000 Pa bar scale, psi to atm conversion for atmosphere comparisons, and pascal conversion for pascal-centered unit changes.
Pitfalls to avoid
- Entering kPa values directly as Pa. A 200 kPa reading should be entered as 200,000 Pa.
- Assuming psi is automatically gauge pressure. Look for psig, psia, or differential labels.
- Rounding 0.000145038 to 0.00015 when a pressure limit is tight.
- Comparing the calculator’s rounded reciprocal with a high-precision metrology value without noting the implemented factor.
- Forgetting that bar and atm are close but not identical; 1 bar is 100,000 Pa, while 1 atm is 101,325 Pa.
Accuracy and limits
The calculator keeps the defined or cited relationship through the calculation and rounds only the displayed result. A converted number does not become more precise than the source measurement. Keep additional digits for chained calculations, then round to the precision justified by the original value; also preserve any reference basis or notation convention named with the input.
Sources
- NIST, SI units — SI context for the pascal.
- NIST, standard atmosphere constant — standard-atmosphere reference for the atm support row.
- BIPM, SI base units — international SI measurement framework.
- NOAA Ocean Service, What is a barometer? — atmospheric-pressure context for comparing Pa, bar, and atm.