Pressure Converter
Convert between pascals, bar, psi, atm, mmHg, and more pressure units instantly.
About the Pressure Converter
Pressure appears across a wider range of everyday contexts than most people realize: tyre maintenance (PSI, bar), blood pressure monitoring (mmHg), weather forecasting (hPa, millibar), industrial equipment (MPa, bar), cooking (pressure cookers operate at 0.7-1 bar above atmospheric), and medical oxygen cylinders (bar, kg per sq cm). Each context uses a different unit because the fields developed independently, and the measurement traditions became entrenched before any global standardization effort.
In India, three pressure contexts dominate daily life. Tyre pressure is specified in PSI (pounds per square inch) on tyre sidewalls and in bar on many Indian service station gauges - and the vehicle manual may show either, making conversion necessary at every service visit. Blood pressure is universally measured in mmHg (millimeters of mercury) based on the historical mercury sphygmomanometer. Atmospheric pressure is reported in hPa or millibar in weather forecasts, particularly cyclone and monsoon alerts from the India Meteorological Department.
For professionals in HVAC, refrigeration, industrial automation, and medical gas supply, pressure unit literacy is a safety requirement. A refrigeration system with a high-side pressure of 18 bar (261 PSI) operates very differently from the same reading interpreted as 18 PSI. Compressed oxygen cylinders for hospitals are rated at 150-200 bar (2,175-2,900 PSI) - unit confusion on a pressurized gas system is a genuine explosion risk. This converter handles all common pressure units with the precision required for both everyday and professional use.
Pressure Conversion Reference
1 bar = 14.504 PSI = 100,000 Pa = 750.06 mmHg · 1 atmosphere = 1.013 bar = 14.696 PSI
Car tyre: 28-36 PSI = 1.9-2.5 bar · Blood pressure: normal 120/80 mmHg · Sea level atmosphere: 1,013.25 hPa = 1 atm · Pressure cooker: 0.7-1 bar above atmospheric
Worked Example
Car tyre recommended at 32 PSI - what is this in bar?
32 PSI = 2.21 bar - most Indian cars recommend 2.0-2.5 bar tyre pressure
Tips & Insights
- 1
For car tyres, the recommended pressure is typically 28-36 PSI (1.9-2.5 bar) depending on vehicle type. Most Indian service stations provide air in bar. Check your door jamb sticker for the exact recommendation in both PSI and bar before inflating.
- 2
Blood pressure is always in mmHg: systolic/diastolic. Normal is below 120/80 mmHg. Stage 1 hypertension begins at 130/80 mmHg. These clinical thresholds are the same worldwide - unlike other pressure units, mmHg has not been metricated in medical practice.
- 3
Weather alerts: standard atmospheric pressure at sea level = 1,013.25 hPa = 1 atm = 14.696 PSI. A monsoon low pressure system at 990 hPa represents a deviation of about 2.3% from standard - enough to significantly alter wind patterns and rainfall distribution.
- 4
Pressure cookers in India operate at 15 PSI (1.03 bar) above atmospheric for standard models, reducing cooking times by 60-70% vs open boiling. The whistle marks pressure release back to atmospheric. At high altitudes (Shimla, Mussoorie), cook for 15-20% longer due to lower base atmospheric pressure.
- 5
For cyclists and motorcyclists, use a digital tyre pressure gauge for accuracy. Road bike tyres need 90-120 PSI (6.2-8.3 bar); mountain bike tyres 25-35 PSI (1.7-2.4 bar); scooters and motorcycles 28-36 PSI (1.9-2.5 bar) front and 36-42 PSI (2.5-2.9 bar) rear.
- 6
Altitude significantly reduces atmospheric pressure. At 2,000 m (Shimla, Mussoorie) atmospheric pressure is about 795 hPa = 0.785 atm. At this pressure, water boils at about 93 C instead of 100 C - pressure cookers and boiling-dependent cooking times need adjustment in hill stations.
- 7
Compressed gas cylinders (welding, medical oxygen) in India are rated in bar or kg/cm^2. Always match regulator markings to cylinder specifications. Natural gas supply pressure at consumer meter is 14-21 mbar (0.2-0.3 PSI); LPG cylinders contain gas at 6-7 bar when full at room temperature.
Why this matters for you
Incorrect tyre pressure is one of the most common and easily preventable causes of road accidents in India. Under-inflated tyres at 25 PSI instead of the recommended 32 PSI increase fuel consumption by 2-3%, reduce tyre life by 15-20%, and significantly increase blowout risk at highway speeds. Yet many Indian drivers do not know their target pressure in both the PSI and bar readings that different gauges display. Understanding the conversion makes tyre maintenance accurate regardless of which gauge the service station provides.
For blood pressure management - India's largest single chronic disease burden with over 220 million hypertensive adults - the mmHg unit is non-negotiable clinically. However, as digital blood pressure monitors from different countries show values differently, and as telehealth consultations with overseas doctors become more common, understanding that blood pressure is always read in mmHg and comparing against the 120/80 threshold (normal) and 140/90 threshold (hypertension) is essential health literacy for any adult.
In manufacturing, construction, and the growing industrial sector, correct pressure specification prevents equipment failure and safety incidents. A pneumatic system rated at 8 bar will fail dangerously if operated at 8 MPa (80 bar - catastrophically high). The pressure specifications on industrial equipment must be read in their stated units and converted correctly before setting regulators or sizing pipework. This converter provides the accurate, cross-system conversions that such work requires.
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Frequently Asked Questions
How many PSI in 1 bar?+
1 bar = 14.5038 psi. 1 psi = 0.0689476 bar. Bar is commonly used for tyre pressure in Europe; psi is common in the US and India. Standard tyre pressure is 30–35 psi (2.07–2.41 bar).
What is atmospheric pressure?+
1 standard atmosphere (atm) = 101,325 Pa = 1.01325 bar = 14.696 psi = 760 mmHg. This is the average air pressure at sea level. Pressure decreases with altitude - at 8,848m (Everest), it's about 0.33 atm.
What is mmHg?+
mmHg (millimeters of mercury) is used in medicine for blood pressure. Normal blood pressure is 120/80 mmHg. 1 mmHg = 133.322 Pa. It's also called torr (1 torr = 1 mmHg exactly).
What is the Pascal (Pa)?+
Pascal is the SI unit of pressure: 1 Pa = 1 N/m². It's a very small unit - 1 bar = 100,000 Pa, 1 atm = 101,325 Pa. Kilopascal (kPa) and megapascal (MPa) are more practical for most engineering uses.
What blood pressure numbers mean and what units are used?+
Blood pressure is measured in mmHg (millimetres of mercury). Normal is below 120/80 mmHg. Elevated is 120-129 with diastolic below 80 mmHg. Stage 1 hypertension is 130-139 over 80-89 mmHg. Stage 2 hypertension is 140 or above over 90 or above mmHg. A hypertensive crisis above 180/120 mmHg is a medical emergency. For Indians, cardiovascular risk increases at lower blood pressure levels than for Caucasians. 1 mmHg = 133.32 Pa. Atmospheric pressure at sea level = 101,325 Pa = 760 mmHg = 1 atm. Weather forecasts use hPa (hectopascals), which are the same as millibars.
What is normal tyre pressure in India and why does it matter?+
Correct tyre pressure varies by vehicle and is specified by the manufacturer on a sticker inside the driver door or in the owner manual. Typical values for Indian cars: hatchbacks and small sedans - 30 to 35 PSI (2.07 to 2.41 bar) front and rear. SUVs and larger sedans: 32 to 36 PSI front, 35 to 40 PSI rear. Motorcycles: front 28 to 32 PSI, rear 32 to 42 PSI. Why it matters: under-inflated tyres (10 PSI below spec) reduce fuel efficiency by 3 to 4%, cause tyres to overheat and wear unevenly (significantly shortening tyre life), and impair braking and handling. Over-inflated tyres wear the centre tread faster, reduce contact patch, and make the ride harsher. Check pressure monthly and always when the tyre is cold (not after driving). Use the PSI measurement even if your petrol station gauge shows bar - convert with 1 PSI = 0.069 bar.
What pressure units are used in Indian engineering and industrial contexts?+
Different industries in India use different pressure units. Pneumatics and hydraulics (factory machinery): bar or MPa (megapascal). 1 bar = 100 kPa = 0.1 MPa. A typical industrial pneumatic cylinder operates at 4 to 7 bar. Hydraulic systems operate at 100 to 700 bar. Blood pressure and medical: mmHg (millimetres of mercury). Weather and meteorology: hPa (hectopascal), numerically equal to millibar. Atmospheric pressure at sea level = 1,013 hPa. Weather apps show pressure in hPa in India. Cooking (pressure cookers): measured in PSI relative to atmospheric pressure. A 15 PSI pressure cooker raises boiling point to approximately 121 degrees C, sterilising food effectively. In civil engineering and soil mechanics: kPa or kN/m squared. In the oil and gas industry (common in Gujarat): MPa or psi. Always verify units when reading pressure specifications, as confusion between absolute and gauge pressure (relative to atmosphere) can lead to significant errors.