Pressure Converter
Convert pressure units online free: bar, psi, atm, Pa, kPa, MPa, mmHg, inHg, torr. Interactive converter with chart and breakdown table. Fast, accurate conversions.
About This Calculator
The Pressure Converter 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 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 conversion result is displayed as an easy-to-read value, accompanied by 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.
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). Atmospheric pressure is reported in hPa by the India Meteorological Department.
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. Atmospheric pressure is reported in inHg by US weather services.
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 Converter work?
The Pressure Converter works by taking your input value, converting it to Pascals (the SI base unit of pressure) using a predefined conversion factor, and then converting from Pascals to your chosen 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 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.
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 the difference between bar and psi?
Bar and psi are two common pressure units. 1 bar equals approximately 14.504 psi, or 100,000 Pascals. Bar is commonly used in Europe and in metric-system countries for tire pressure, weather maps, and industrial processes. Psi (pounds per square inch) is widely used in the United States for tire pressure, HVAC systems, and hydraulic applications.
What is the 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 tire pressure from bar to psi?
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. Many tire pressure specifications are given in bar in most countries and psi in the United States. This converter handles the conversion instantly in both directions.
What is the relationship 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, which is also 133.322 Pa. For practical purposes, 1 mmHg = 1 Torr, and both are used in vacuum measurements and blood pressure readings.
Can I convert pressure 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 applications such as material stress testing, hydraulic systems, and fluid dynamics calculations.