Pressure Converter
Looking for a free online pressure conversion calculator? Easily convert between Pascal, Kilopascal, PSI, Bar, Millibar, Torr, and more with precision and speed. Perfect for engineering, science, automotive work, and industrial applications. Quick, accurate, and completely free to use!
Understanding the Conversion
Need to convert pressure values quickly without memorizing every factor? This pressure converter lets you switch instantly between Pascal (Pa), Kilopascal (kPa), PSI (pounds per square inch), Bar, Millibar (mbar), and Torr. It is designed for real-world work across HVAC, automotive tires, hydraulics, pneumatics, diving, meteorology, laboratory and vacuum systems, and industrial process control.
Pressure units differ by both scale and typical use. Pascal is the SI base unit; Kilopascal scales it for everyday engineering and weather reporting. PSI is common in the U.S. for tires, hydraulics, and compressors. Bar and Millibar appear in industrial specs and weather maps. Torr is used for vacuum and lab measurements. Because these units share well-defined linear relationships (e.g., 1 kPa = 1000 Pa, 1 bar = 100 kPa, 1 atm ≈ 101.325 kPa ≈ 14.6959 psi ≈ 760 Torr ≈ 1013.25 mbar), conversions are precise and repeatable.
This page provides clear formulas, step-by-step examples, reference charts, and quick tips so you can move from one unit to another with confidence. Whether you are setting tire pressures, sizing a compressor, checking HVAC static pressure, estimating scuba depth pressure, interpreting weather maps, or validating vacuum levels in the lab, this converter keeps numbers consistent and easy to share with teams and clients.
Key reference points to remember: sea-level pressure is about 101.325 kPa (1 atm) or 14.7 psi or 1.01325 bar or 1013.25 mbar or 760 Torr. Typical car tires run around 32–35 psi (220–240 kPa). Light vacuum work may be in tens of kPa, while high-vacuum systems track down to fractions of a Torr or a few Pascals. Knowing these anchors helps sanity-check results before acting on them.
All conversions on this site are formula-driven, instant, and free to use. Enter a value, pick your From and To units, and the calculator handles the math on mobile or desktop with no sign-up required.
Common Use Cases
- HVAC and building systems: convert static pressure or differential pressure between Pa, kPa, and in-field psi/bar readings.
- Automotive and transport: translate tire pressures between psi and kPa/bar for manuals, TPMS sensors, and shop equipment.
- Hydraulics and pneumatics: move between kPa, bar, and psi for cylinders, pumps, regulators, and safety limits.
- Meteorology and weather: interpret forecasts and station data in mbar, kPa, or bar, and compare to standard atmosphere.
- Diving and marine: relate bar and psi to depth and equipment ratings for scuba or ROV operations.
- Laboratory and vacuum systems: convert Torr, Pa, and mbar for vacuum chambers, leak tests, and instrumentation.
- Industrial process and QA: align supplier specs and SOPs across Pa/kPa/bar/psi to ensure consistent tolerances and compliance.
- Education and exams: practice pressure formulas and reference points across SI and Imperial units.
Frequently Asked Questions
Which pressure units does this converter support?
The converter supports Pascal (Pa), Kilopascal (kPa), PSI (pounds per square inch), Bar, Millibar (mbar), and Torr. These cover most HVAC, automotive, industrial, meteorology, and laboratory use cases.
How are the conversions calculated?
All conversions use fixed, internationally recognized relationships: 1 kPa = 1000 Pa, 1 bar = 100 kPa, 1 psi ≈ 6.89476 kPa, 1 mbar = 100 Pa, 1 Torr ≈ 133.322 Pa, and 1 atm ≈ 101.325 kPa ≈ 14.6959 psi ≈ 760 Torr. The calculator applies these factors precisely.
What is a good reference for sea-level pressure?
Standard atmospheric pressure at sea level is about 101.325 kPa, 14.7 psi, 1.01325 bar, 1013.25 mbar, or 760 Torr. Use these anchors to sanity-check conversions.
Why do tires list psi while some manuals list kPa?
North American tire gauges and placards often use psi, while many manuals and global standards list kPa. Converting between psi and kPa ensures correct inflation regardless of the unit shown on the gauge or the door sticker.
How do I convert between gauge pressure and absolute pressure?
Gauge pressure measures relative to ambient atmosphere; absolute pressure adds atmospheric pressure (~101.325 kPa at sea level). Add atmospheric pressure to gauge readings to get absolute, or subtract to go from absolute to gauge.
What ranges should I expect for vacuum readings?
Rough vacuum often measures in kPa or mbar, while high and ultra-high vacuum are in Torr or Pascals. For example, 1 Torr ≈ 133.322 Pa, and high vacuum may be below 10⁻³ Torr.
Is the converter free to use?
Yes. The converter is free, requires no sign-up, and works on desktop or mobile. Just enter a value and choose your units.
Can I enter decimal values or large numbers?
Absolutely. Enter decimals (e.g., 2.3 bar or 32.5 psi) or large values (e.g., 5,000,000 Pa). The tool keeps precision and applies the exact factors.