Pressure Converter: Convert Between Pressure Units
Pressure measurements appear in weather forecasting, tire inflation, scuba diving, HVAC systems, hydraulic engineering, and scientific research — often in different units depending on your country or industry. Our free online Pressure Converter handles conversions between psi, bar, pascals, kilopascals, atmospheres, torr, millimeters of mercury, and inches of mercury. Get accurate pressure conversions for any application with a single click.
Standard Pressure Conversion Reference
| Unit | Equivalent Value |
|---|---|
| 1 Atmosphere (atm) | 14.696 psi | 101.325 kPa | 1.01325 bar | 760 torr | 29.92 inHg |
| 1 Bar | 100 kPa | 14.504 psi | 0.987 atm | 750.06 torr |
| 1 PSI (lb/in²) | 6.895 kPa | 0.069 bar | 0.068 atm | 51.715 torr |
| 1 Pascal (Pa) | 0.001 kPa | 0.00001 bar | 0.000145 psi |
| 1 Kilopascal (kPa) | 0.145 psi | 0.01 bar | 0.00987 atm | 7.501 torr |
| 1 Torr (mmHg) | 0.001316 atm | 0.01934 psi | 0.1333 kPa | 0.03937 inHg |
| 1 inHg | 0.0334 atm | 0.491 psi | 3.386 kPa | 25.4 torr |
How to Use the Pressure Converter
Using our pressure converter is straightforward. Select your starting unit from the dropdown menu (for example, PSI), enter the numeric value, then choose the target unit (such as bar). The tool instantly displays the equivalent value using precise conversion factors. For example, entering 32 PSI (standard car tire pressure) converts to 2.21 bar or 220.6 kPa. The converter supports two-way conversion, so you can swap input and output units with a single tap. All results are rounded to four decimal places for maximum accuracy while remaining readable for everyday use.
How the Converter Works: The Bar as a Reference
Every conversion in the tool passes through a single reference unit. Internally, the converter holds a rate for each unit expressed relative to 1 bar, then computes: value in the source unit × source rate ÷ target rate. Because both the "from" and "to" units share the same reference, every pair converts correctly and the arithmetic stays consistent no matter how unusual the combination.
You can watch this work with real values. Convert 32 PSI to kPa: 32 × 0.0689476 = 2.206 bar, then 2.206 ÷ 0.01 = 220.6 kPa. Convert the same 32 PSI to bar directly: 32 × 0.0689476 = 2.206 bar. One division step different, same answer — the bar simply drops out when bar is the target unit. Convert 1 atmosphere to PSI: 1 × 1.01325 = 1.01325 bar, then 1.01325 ÷ 0.0689476 = 14.696 PSI, the standard sea-level value.
Two unit pairs in the table share the same rate: mmHg and torr both carry 0.00133322, which reflects the relationship 1 mmHg ≈ 1 torr. Convert 760 mmHg to torr and you get 760 torr, a conversion so common in vacuum and laboratory work that the tool makes it immediate. The reference table also explains the decimals you see in results — each rate is a fixed constant (1 PSI = 6.89476 kPa, 1 atm = 101.325 kPa), and the calculator simply chains them through bar.
Because results are rounded to six decimal places, small rounding may appear on extreme conversions — converting a very large pascal value to atm can trail into the fifth or sixth decimal. For everyday tire, weather, and diving checks that precision is more than sufficient; for lab-grade work, treat the final digit as a rounding artifact and keep your source figures to the same level of precision.
Practical Use Cases for Pressure Conversion
Tire Inflation: Car tire pressure is measured in PSI in the United States but in bar or kPa in Europe and Asia. Our converter helps you check manufacturer recommendations regardless of which unit they use. For example, a recommendation of 2.2 bar equals 32 PSI.
Weather Forecasting: US weather reports use inches of mercury (inHg) for barometric pressure, while the rest of the world uses hectopascals (hPa) or millibars (mbar). Storm systems typically form below 29.92 inHg (1013.25 hPa).
Scuba Diving: Tank pressure is commonly measured in PSI in the US and bar elsewhere. A standard aluminum 80 tank filled to 3,000 PSI equals about 207 bar. Understanding both units is critical for dive safety.
HVAC and Refrigeration: Technicians measure refrigerant pressure in PSI or kPa. Converting between units helps when using equipment or documentation from different manufacturers. Operating pressures for R-410A systems typically range from 120-150 PSI on the low side.
Vacuum Systems: Industrial vacuum is measured in torr or mbar. Choosing the right pump requires accurate pressure conversion — 1 torr equals 1.333 mbar.
Tips for Accurate Pressure Conversion
Always verify which pressure standard your application uses — gauge pressure (psig) versus absolute pressure (psia) differs by one atmosphere (14.696 psi). For tire pressure, use gauge pressure. For gas law calculations in science, use absolute pressure. Our converter uses absolute pressure conventions. Also note that some industries use unique units: medical blood pressure in mmHg, meteorology in hPa, and deep-sea measurements in atmospheres. If you need additional related conversions, check our Temperature Converter for gas law calculations and our Energy Converter for thermodynamic conversions.
Keywords: pressure converter, psi to bar, convert pressure, atm to psi, kPa to psi, tire pressure conversion, barometric pressure, unit converter pressure, inHg to hPa, scuba tank pressure, HVAC pressure units
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Written by the CalcMaster Pro Editorial Team — financial, health, and DIY tools reviewed for accuracy. All calculators run on standard, widely accepted formulas. Always confirm final numbers with a qualified professional for decisions that require official figures.