Pressure Converter
Convert between PSI, bar, pascal, and atmosphere.
How to use Pressure Converter
Enter Your Pressure Value
Click the input field labeled 'Enter pressure value' and type your numerical measurement. You can enter decimals (e.g., 14.7, 101.325) for precise conversions.
Select Your Source Unit
Click the 'From unit' dropdown menu and choose your starting pressure unit: PSI (pounds per square inch), bar, pascal (Pa), or atmosphere (atm). The dropdown displays all four options clearly.
Choose Your Target Unit
Click the 'To unit' dropdown menu and select which unit you want to convert to. The conversion calculates instantly as you select, displaying the result in the 'Converted value' field below.
Copy or Reset Your Result
Click the blue 'Copy' button next to your result to copy the converted value to clipboard. Click 'Reset' to clear all fields and start a new conversion.
Related Tools
Pressure converter: pascal, bar, psi, atm, mmHg, and more
Pressure converter: pascal, bar, psi, atm, mmHg, and more
Convert between pascal, kilopascal, bar, psi, atm, mmHg, and inHg at ToolHQ's pressure converter, all common pressure units with instant results. Free, no account required.
Pressure is force applied per unit area. Different fields settled on different units: the US automotive industry uses psi, European industrial equipment uses bar, medical equipment uses mmHg, meteorology uses kPa and inHg, and physics uses the SI unit pascal (Pa). Converting between them accurately requires the right reference values.
ToolHQ's pressure converter handles all seven common pressure units and returns all equivalents simultaneously from a single input.
Key Takeaways
- 1 atm = 101,325 Pa = 14.696 psi = 1.01325 bar = 760 mmHg = 29.92 inHg
- Psi is standard for US automotive (tire pressure, fuel pressure)
- mmHg is the standard unit for blood pressure worldwide
- Bar is standard for industrial and European pressure measurements
- kPa is used for weather (barometric) pressure in most countries
- No data is stored or transmitted, all calculations run locally in your browser
Pressure unit overview: which unit is used where
| Unit | Full name | Field | Region |
|---|---|---|---|
| Pa | Pascal | Science, SI base unit | Global |
| kPa | Kilopascal | Weather, meteorology | Global (outside US) |
| MPa | Megapascal | High-pressure engineering | Global |
| bar | Bar | Industrial, diving, hydraulics | Europe, global industrial |
| psi | Pounds per square inch | Automotive, plumbing, pneumatics | US and UK |
| atm | Atmosphere | Chemistry, diving, general reference | Global |
| mmHg / Torr | Millimeters of mercury | Blood pressure, medical, vacuum | Global |
| inHg | Inches of mercury | Aviation altitude, US weather | United States |
Quick field guide:
- Car tire pressure: psi in the US, bar in Europe, kPa in some countries (30 psi = 2.07 bar = 207 kPa)
- Blood pressure: mmHg everywhere (120/80 mmHg is the standard notation)
- Barometric weather pressure: kPa or hPa globally, inHg in US weather reports (29.92 inHg = standard sea-level pressure)
- Industrial hydraulics: bar in Europe, psi in the US
- Scientific chemistry: atm or Pa
All calculations run locally in your browser, no data is stored or transmitted.
Gauge pressure vs. absolute pressure
Many pressure readings are "gauge pressure", they measure pressure relative to the atmosphere, not relative to a perfect vacuum. Understanding this distinction matters for conversions:
Absolute pressure = total pressure measured from a perfect vacuum. Gauge pressure = pressure above atmospheric (what most gauges read). Relationship: Absolute = Gauge + Atmospheric (1 atm = 101.325 kPa = 14.696 psi)
Examples:
- A car tire rated at 32 psi is 32 psi gauge pressure. The absolute pressure inside the tire is 32 + 14.696 = 46.7 psia (psi absolute).
- Blood pressure of 120/80 mmHg is gauge pressure relative to atmospheric, 120 mmHg above ambient.
- Vacuum pressure is expressed as negative gauge pressure or as absolute pressure below 1 atm.
For everyday unit conversions (tire pressure, HVAC, plumbing), gauge pressure readings can be directly converted between units without worrying about the absolute vs. gauge distinction, since you are just changing the scale.
Standard atmospheric pressure reference table
One standard atmosphere (1 atm) is the reference point for nearly all pressure comparisons:
| Unit | Value of 1 atm |
|---|---|
| Pascal (Pa) | 101,325 Pa |
| Kilopascal (kPa) | 101.325 kPa |
| Millibar (mbar) | 1,013.25 mbar |
| Bar | 1.01325 bar |
| PSI (psi) | 14.696 psi |
| mmHg (Torr) | 760 mmHg |
| inHg | 29.921 inHg |
Tip: 1 bar is close to 1 atm but not exactly the same. In engineering, bar is often used as an approximation for atmospheric pressure. The exact value matters in precision science but is negligible for most practical applications.
Mini-story 1: Carlos was filling his car tires before a long road trip. The sticker in the door jamb said 35 psi. His garage had a European pressure gauge that displayed bar. He entered 35 psi into ToolHQ's pressure converter and got 2.41 bar. He pumped his tires to 2.41 bar and was good to go. He also saw that 35 psi = 241.3 kPa, which the newer digital display on the tire inflator at the gas station used.
Convert pressure units free at ToolHQ
How to use the ToolHQ pressure converter
- Go to the tool. Navigate to ToolHQ's pressure converter. No account or sign-up required.
- Enter your value. Type any number in the input field.
- Select your source unit. Choose from Pa, kPa, MPa, bar, psi, atm, mmHg, or inHg.
- Read all results. The converter returns the equivalent in all supported units simultaneously.
Common pressure conversion examples
| Scenario | Input | Converted value |
|---|---|---|
| Car tire pressure (US standard) | 32 psi | 2.21 bar / 220.6 kPa |
| Car tire pressure (Europe) | 2.2 bar | 31.9 psi / 220 kPa |
| Normal blood pressure (systolic) | 120 mmHg | 16 kPa / 2.32 psi |
| Standard sea-level air pressure | 1 atm | 101.325 kPa / 14.696 psi |
| US weather report (barometric) | 30 inHg | 101.59 kPa / 1.016 bar |
| Scuba diving at 10 m depth | 2 atm | 202.65 kPa / 29.39 psi |
| HVAC refrigerant high side (R-410A) | 400 psi | 27.6 bar / 2,758 kPa |
For temperature pressure relationships (ideal gas law calculations), ToolHQ's unit converter handles temperature alongside other physical units.
Mini-story 2: Dr. Sarah was working with a medical device specification from a European manufacturer. The device's pressure sensor was rated in kPa, but her hospital's existing monitoring system used mmHg for all pressure readings. The specification said the sensor maximum was 40 kPa. She entered 40 kPa into ToolHQ's pressure converter and got 300 mmHg, well above the normal blood pressure range (80-120 mmHg systolic) and safely within the operating range for the monitoring device. She recorded 300 mmHg as the sensor ceiling in the hospital documentation.
Frequently asked questions
What is the difference between psi and bar?
Both measure pressure (force per unit area). Psi (pounds per square inch) is the US and UK standard. Bar is the European and international industrial standard. 1 bar = 14.504 psi. Standard atmospheric pressure is 14.696 psi = 1.01325 bar.
Why is blood pressure measured in mmHg?
mmHg (millimeters of mercury) comes from the mercury manometers that were the standard medical pressure measurement instrument for centuries. A reading of 120 mmHg means the pressure would raise a column of mercury 120mm high. The unit persists globally because medical conventions change slowly and existing equipment, literature, and training all use mmHg.
What is the difference between gauge pressure and absolute pressure?
Gauge pressure is measured relative to atmospheric pressure. Absolute pressure is measured relative to a perfect vacuum. For most everyday conversions (tire pressure, blood pressure, weather), readings are gauge pressure. Add 1 atm (14.696 psi, 101.325 kPa, 1.01325 bar) to gauge pressure to get absolute pressure.
What pressure do tires use?
Car tire pressure is typically 30-35 psi (2.07-2.41 bar) for passenger vehicles. Check the sticker on your door jamb or the owner's manual for the specific recommended pressure for your vehicle, and note whether the measurement is in psi, bar, or kPa.
Is the pressure converter free?
Yes. ToolHQ's pressure converter is completely free, with no account, no sign-up, and no usage limits.
The short version
Pressure units divide by field and geography: psi in the US for automotive and plumbing, bar for European industrial systems, mmHg for medical, kPa for weather, and Pa for science. The standard reference point is 1 atm = 101,325 Pa = 14.696 psi = 1.01325 bar = 760 mmHg = 29.92 inHg. The gauge vs. absolute pressure distinction matters in precision work but not for most everyday conversions. ToolHQ's pressure converter handles all seven units simultaneously, returning every equivalent from a single input.
For related tools, ToolHQ's unit converter covers length, weight, temperature, and volume conversions, and the energy converter handles joules, BTU, and kilowatt-hours. Explore more converter tools at ToolHQ.
Convert pressure units free at ToolHQ