Pressure Unit Conversion
Convert pressure units online free: bar, psi, atm, Pa, kPa, MPa, mmHg, inHg, and torr. Interactive pressure converter with comparison chart and breakdown table for fast, accurate results.
About This Calculator
The Pressure Unit Conversion calculator is a free online tool that lets you convert between 10 different pressure units instantly: Pascal (Pa), hectopascal (hPa), kilopascal (kPa), megapascal (MPa), atmosphere (atm), bar, pounds per square inch (psi), millimeter of mercury (mmHg), inch of mercury (inHg), and torr. Whether you work in engineering, meteorology, automotive, HVAC, medicine, or scientific research, this tool handles all your pressure unit conversion needs with precision and speed.
The conversion works by first converting your input value to the SI base unit Pascal using the internationally recognized conversion factor, then converting from Pascals to the target unit. This two-step approach ensures maximum accuracy across all unit pairs. For example, to convert 2.5 bar to psi, the tool multiplies 2.5 by 100,000 to get 250,000 Pa, then divides by 6,894.76 to yield approximately 36.26 psi. Each result displays alongside a comprehensive breakdown table showing the equivalent pressure in every supported unit.
A visual bar chart compares the converted value across all units, making it simple to understand relative magnitudes — especially useful when switching between metric (bar, kPa) and imperial (psi) systems. The chart helps visualize how pressure values relate across different unit systems at a glance.
Regional Notes
India (IN): Bar and kPa are commonly used in engineering and industrial applications. Tire pressure is often measured in bar (e.g., 32–35 psi ≈ 2.2–2.4 bar). The India Meteorological Department reports atmospheric pressure in hPa.
United States (US): Psi is the standard unit for tire pressure, HVAC systems, hydraulic applications, and most industrial gauges. Blood pressure is measured in mmHg. US weather services report atmospheric pressure in inHg.
United Kingdom (UK): Bar is widely used for tire pressure, while kPa and MPa are common in engineering. Blood pressure uses mmHg. The UK Met Office reports atmospheric pressure in hPa.
Frequently Asked Questions
How does the Pressure Unit Conversion calculator work?
The Pressure Unit Conversion calculator works by taking your input value in the source unit, converting it to Pascals (the SI base unit of pressure) using a predefined conversion factor, then converting from Pascals to the target unit. For example, 1 bar equals 100,000 Pa and 1 psi equals 6,894.76 Pa. The tool instantly displays the converted result plus a comparison chart and breakdown table showing the value across all supported pressure units.
How many pressure units are supported?
The converter supports 10 pressure units: Pascal (Pa), hectopascal (hPa), kilopascal (kPa), megapascal (MPa), atmosphere (atm), bar, pounds per square inch (psi), millimeter of mercury (mmHg), inch of mercury (inHg), and torr (Torr). These cover SI, metric, imperial, and scientific unit systems used worldwide in engineering, meteorology, automotive, and medicine.
Is the pressure conversion accurate?
Yes, all conversions use scientifically accepted standard conversion factors. Each pressure unit is converted through the SI base unit Pascal to ensure precision. The conversion factors follow international standards such as NIST and BIPM for maximum accuracy across scientific, engineering, and industrial applications.
What is standard atmospheric pressure at sea level?
Standard atmospheric pressure at sea level is defined as 1 atm, which equals 101,325 Pa, 1,013.25 hPa, 1.01325 bar, 14.696 psi, 760 mmHg, 29.92 inHg, or 760 Torr. Meteorologists often use hectopascals (hPa) for atmospheric pressure reporting, where standard pressure is 1,013.25 hPa.
How do I convert bar to psi for tire pressure?
To convert tire pressure from bar to psi, multiply the bar value by 14.504. For example, 2.2 bar × 14.504 = 31.9 psi. In the US, tire pressure is measured in psi, while most other countries use bar. This converter handles the conversion instantly in both directions.
What is the difference between mmHg and torr?
Millimeters of mercury (mmHg) and torr are nearly identical units of pressure. Both originate from the mercury barometer. By definition, 1 mmHg is approximately 133.322 Pa, and 1 torr equals 1/760 of an atmosphere, also 133.322 Pa. For practical purposes, 1 mmHg = 1 Torr, and both are used in vacuum measurements and blood pressure readings.
Can I use this converter for scientific and engineering applications?
Yes, this converter supports all major pressure units used in science and engineering including Pa, hPa, kPa, MPa, bar, and atm. Scientists working with SI units can use Pascals and its multiples, while engineers can switch between bar, psi, and MPa for material stress testing, hydraulic systems, and fluid dynamics calculations.
What units are used for blood pressure measurement?
Blood pressure is universally measured in millimeters of mercury (mmHg). For example, a normal blood pressure reading is 120/80 mmHg. This converter can convert mmHg to other pressure units such as kPa or atm for medical research and international reporting standards.