Pressure Converter
Convert between common pressure units instantly. Perfect for engineering, weather, automotive, and scientific applications.
How to Use the Pressure Converter
Converting between pressure units is quick and straightforward:
- Enter a numeric value in the input field. Decimals are supported for precision.
- Select the source unit from the dropdown (Pascal, Bar, PSI, ATM, mmHg, or inHg).
- View all conversions in the results table. Results appear instantly as you type.
- Click Copy next to any result to copy the value to your clipboard.
About Pressure Units
Pressure is the force applied per unit area. The SI unit is the Pascal (Pa), named after mathematician Blaise Pascal. In everyday use, many different pressure units exist for different fields. Bar and kilopascal are common in meteorology and engineering. PSI (pounds per square inch) is standard in the United States for tire pressure and hydraulics. Atmospheres (atm) provide an intuitive reference to sea-level air pressure.
Medical professionals often use mmHg (millimeters of mercury) for blood pressure, while aviators use inHg (inches of mercury) for altimeter settings. Key relationships: 1 atm = 101,325 Pa = 1.01325 bar = 14.696 PSI = 760 mmHg = 29.9213 inHg. Understanding these conversions is essential for HVAC, automotive, weather forecasting, and medical applications.
Common Pressure Conversions
The table below provides quick reference values for the most commonly needed pressure conversions, covering atmospheric, automotive, medical, and industrial applications.
| PSI | Bar | kPa | ATM | Context |
|---|---|---|---|---|
| 14.696 | 1.01325 | 101.325 | 1.0 | Standard atmosphere |
| 30 | 2.069 | 206.84 | 2.04 | Low tire pressure |
| 35 | 2.413 | 241.32 | 2.38 | Typical car tire pressure |
| 50 | 3.447 | 344.74 | 3.40 | Truck tire pressure |
| 100 | 6.895 | 689.48 | 6.80 | Road bike tire |
| 150 | 10.342 | 1,034.21 | 10.20 | Compressed air tools |
| 3,000 | 206.84 | 20,684 | 204.07 | Scuba tank |
Pressure Conversion Formulas
Pressure conversions use the Pascal (Pa) as the SI base unit. The key conversion factors between common units are listed below with worked examples.
PSI to Bar: bar = PSI × 0.0689476
Bar to PSI: PSI = bar × 14.5038
ATM to PSI: PSI = ATM × 14.696
PSI to kPa: kPa = PSI × 6.89476
Bar to kPa: kPa = bar × 100
ATM to mmHg: mmHg = ATM × 760
Worked Examples
- Convert 32 PSI to bar: bar = 32 × 0.0689476 = 2.206 bar
- Convert 2.5 bar to PSI: PSI = 2.5 × 14.5038 = 36.26 PSI
- Convert 1013.25 hPa to ATM: First, hPa to Pa: 1013.25 × 100 = 101,325 Pa. ATM = 101,325 ÷ 101,325 = 1.0 ATM
- Convert 120 mmHg (blood pressure) to kPa: kPa = 120 × 0.133322 = 15.999 kPa
When You Need This Converter
Pressure conversion is essential across many industries and everyday situations:
- Automotive Maintenance: Tire pressure gauges in the US display PSI, while European gauges often show bar or kPa. Converting between these units ensures proper tire inflation for safety and fuel efficiency. Knowing that 35 PSI is about 2.41 bar prevents confusion at gas stations abroad.
- Weather and Aviation: Weather reports use different pressure units by region: millibars (hPa) in meteorology, inHg in US weather broadcasts, and mmHg historically. Pilots set altimeters using local pressure in inHg (US) or hPa (international), making conversion a safety-critical skill.
- Medical Applications: Blood pressure is universally measured in mmHg (millimeters of mercury). Medical equipment like ventilators and oxygen systems may display pressure in cmH2O, kPa, or mbar. Healthcare professionals need to convert between these units for accurate patient care.
- HVAC and Industrial Engineering: Heating, ventilation, and air conditioning systems specify pressure in PSI, bar, or kPa. Hydraulic systems, pneumatic tools, and compressed gas cylinders all require accurate pressure conversion for safe operation and regulatory compliance.
Frequently Asked Questions
One bar equals approximately 14.5038 PSI. To convert bar to PSI, multiply the bar value by 14.5038. One bar is also equal to 100,000 Pascal.
Standard atmospheric pressure (1 ATM) equals 101,325 Pascal, 1.01325 bar, 14.696 PSI, 760 mmHg, or 29.9213 inHg. It is defined as the average pressure at sea level.
For practical purposes, mmHg and Torr are identical. One Torr equals exactly 1/760 of a standard atmosphere. The mmHg unit originally referred to the height of a mercury column, and 1 mmHg = 133.322 Pascal.
Inches of mercury (inHg) is commonly used in aviation (altimeter settings) and weather reporting in the United States. Standard pressure is 29.92 inHg.
Typical passenger car tire pressure is 30-35 PSI, which is approximately 2.07-2.41 bar. Check your vehicle's door jamb sticker or owner's manual for the recommended pressure. Bicycle tires can range from 30 PSI (mountain bikes) to over 100 PSI (road bikes).
Normal blood pressure is considered to be below 120/80 mmHg, where 120 mmHg is the systolic pressure and 80 mmHg is the diastolic pressure. High blood pressure (hypertension) is generally defined as 130/80 mmHg or higher.
Divide the PSI value by 14.5038 to get bar. Alternatively, multiply PSI by 0.0689476. For example, 35 PSI = 35 × 0.0689476 = 2.413 bar.
A Pascal (Pa) is one Newton per square meter, the SI unit of pressure. It is a very small unit because one Newton spread over one square meter creates very little pressure. Atmospheric pressure is about 101,325 Pa, which is why kilopascals (kPa) and bar are more practical for everyday use.