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Pressure Converter 2026 | Pascal ↔ PSI ↔ Bar ↔ mmHg | Global Tool

Professional Pressure Converter 2026. Convert Pascal, kilopascal, megapascal, PSI, bar, atm, mmHg, Torr and inHg with ISO-accurate precision. Trusted worldwide for engineering, medical, scientific and industrial applications.

What Is a Pressure Converter?

A pressure converter is a calculation tool that instantly translates a pressure measurement from one unit to another — for example, converting PSI to bar, pascals to kilopascals, or mmHg to atmospheres. It is used daily by mechanical engineers, HVAC technicians, medical professionals, meteorologists, tyre service centres, hydraulic systems designers, and laboratory scientists worldwide.

Pressure measurement is one of the most unit-fragmented domains in engineering. The SI unit — the pascal — is universally accepted in science, yet the bar dominates European industrial practice, PSI remains standard in the USA and UK, mmHg is the global medical standard for blood pressure, and atmospheres appear in diving and chemistry. This tool handles all of these systems accurately and converts between them in real time.

How to Use This Pressure Converter

Results appear in real time as you type — no submit button required.

  1. Enter the value — Type the numeric pressure you want to convert. Decimals and very large or very small values are fully supported.
  2. Select the source unit — Choose the unit your original pressure is expressed in, such as PSI, bar, or pascal.
  3. Select the target unit — Choose the unit you need the result in, such as kPa, atm, or mmHg.
  4. Read the result — The converted value appears instantly with full-precision output.

Supported Pressure Units

This converter covers all major pressure units used globally:

  • SI / Metric: pascal (Pa), kilopascal (kPa), megapascal (MPa), gigapascal (GPa), hectopascal (hPa)
  • Technical / Industrial: bar, millibar (mbar), pounds per square inch (PSI / psi), pounds per square foot (psf)
  • Atmospheric / Meteorological: standard atmosphere (atm), technical atmosphere (at), inches of mercury (inHg), inches of water column (inH₂O)
  • Medical / Vacuum: millimeters of mercury (mmHg), torr, centimeters of water (cmH₂O)
  • Specialized: kilogram-force per square centimeter (kgf/cm²), newton per square meter (N/m²)

Most Common Pressure Conversions

PSI to Bar

Multiply the PSI value by 0.0689476. PSI (pounds per square inch) is the standard in the USA and UK for tyre pressure, hydraulic systems, and compressed air. Bar is the standard in Europe and most industrial contexts worldwide. A typical car tyre inflated to 32 PSI equals approximately 2.21 bar.

Bar to PSI

Multiply by 14.5038. This inverse conversion is used whenever a European-rated pressure gauge value (in bar) must be communicated to a US or UK audience, or when an import product specification is being verified against domestic equipment.

Pascal to Kilopascal (Pa → kPa)

Divide by 1,000. The pascal is the SI base unit for pressure but is extremely small — 1 Pa ≈ the pressure of a bank note resting on a table. Most engineering and meteorological work uses kPa (or hPa for atmospheric pressure reports).

Kilopascal to PSI (kPa → PSI)

Multiply by 0.145038. This conversion appears constantly in automotive repair manuals and specification sheets that cite both metric and imperial tyre pressures.

mmHg to Kilopascal (mmHg → kPa)

Multiply by 0.133322. A normal resting blood pressure of 120/80 mmHg equals approximately 16.0/10.7 kPa. This conversion is used in clinical research, anaesthesia records, and medical device specifications for international markets.

Atmospheres to Pascals (atm → Pa)

Multiply by 101,325. One standard atmosphere is defined as exactly 101,325 Pa. This conversion underpins chemistry and physics calculations involving gas laws (Boyle's Law, the ideal gas law) where SI units are required.

Understanding Your Conversion Results

All conversion factors in this tool are based on exact SI definitions and the internationally accepted values published by the National Institute of Standards and Technology (NIST), the International Organization for Standardization (ISO), and BIPM. Results are displayed rounded for readability; internal arithmetic uses full IEEE 754 double precision to prevent accumulated rounding error across conversion chains.

Gauge Pressure vs. Absolute Pressure

A critical distinction in pressure measurement is the reference point used:

  • Absolute pressure (psia, bara, kPa abs) — measured relative to a perfect vacuum (0 pressure). Used in science, aviation altitude calculations, and thermodynamics.
  • Gauge pressure (psig, barg, kPag) — measured relative to ambient atmospheric pressure. Used in tyre inflation, hydraulic systems, and most industrial processes. A gauge reading of 0 means the system is at atmospheric pressure, not a vacuum.

To convert gauge pressure to absolute: add approximately 101.325 kPa (14.696 PSI / 1.01325 bar) — the standard atmospheric pressure at sea level. This converter works with absolute values; always confirm the reference point in your application.

Medical Pressure: mmHg and Blood Pressure

Millimeters of mercury (mmHg) has been the standard unit for blood pressure measurement globally since the sphygmomanometer was invented in 1896. Despite the SI system defining kPa as the preferred medical pressure unit, mmHg remains dominant in clinical practice worldwide — including the USA, UK, EU, India, China, and Japan — due to decades of established reference ranges.

Example Calculations

Example 1 — Tyre Pressure: PSI to Bar

Scenario: A car manufacturer's US handbook recommends 35 PSI front tyre pressure. A European service technician needs the value in bar.

35 PSI × 0.0689476 = 2.413 bar. The technician sets the tyre inflator to 2.4 bar (practically equivalent given gauge resolution).

Example 2 — Hydraulic System: bar to MPa

Scenario: An industrial hydraulic press operates at 250 bar. The engineering report requires the value in megapascals for ISO documentation.

250 bar × 100,000 Pa/bar ÷ 1,000,000 Pa/MPa = 25 MPa.

Example 3 — Meteorology: hPa to inHg

Scenario: A weather station reports barometric pressure as 1013 hPa. A US pilot needs the value in inches of mercury (inHg) for the aircraft altimeter.

1013 hPa × 0.02953 = 29.91 inHg — effectively standard sea-level atmospheric pressure (standard = 29.92 inHg).

Pressure Units by Application Domain

Automotive & Pneumatics

Tyre pressure is expressed in PSI in the USA, UK, India, and many other markets; in bar or kPa in continental Europe, Japan, and Australia. Compressed air systems use bar (EU) or PSI (USA/UK). Correct tyre inflation is critical for fuel economy, tyre wear, and safety — always verify units before adjusting pressure.

Industrial & Hydraulic Engineering

Hydraulic systems are rated in bar (Europe) or PSI (North America). High-pressure applications such as waterjet cutting (up to 6,200 bar / 90,000 PSI) and oil-well drilling use MPa or kpsi. Boiler and pressure vessel standards (ASME, EN 13445) specify operating limits in bar or PSI depending on the originating standard.

Medical & Life Sciences

Blood pressure: mmHg (universal clinical standard). Respiratory ventilators and anaesthesia equipment: cmH₂O or mbar for airway pressures. Hyperbaric oxygen therapy chambers: atm or bar. Intraocular pressure (eye): mmHg. Cerebrospinal fluid pressure: cmH₂O or mmHg.

Meteorology & Aviation

Atmospheric pressure in weather forecasting: hPa (identical to mbar) globally, except the USA which also uses inHg. Aircraft altimeters: inHg (USA, Canada) or hPa (rest of world, per ICAO annex 5). Standard atmosphere = 1013.25 hPa = 29.921 inHg = 101.325 kPa.

Help & FAQs

Frequently Asked Questions

Clear answers to common questions to help you use this calculator confidently.

What is a Pressure Converter?

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A Pressure Converter helps you instantly convert between pressure units such as Pascal (Pa), kilopascal (kPa), megapascal (MPa), bar, PSI (pounds per square inch), standard atmosphere (atm), millimeters of mercury (mmHg), torr, and inches of mercury (inHg). It is used in engineering, automotive maintenance, medical devices, meteorology, HVAC, hydraulic systems, and scientific research worldwide.

What is the SI unit of pressure?

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The SI (International System of Units) unit of pressure is the pascal (Pa). Larger values are commonly expressed as kilopascal (kPa) or megapascal (MPa). One pascal equals one newton per square meter (N/m²). It is the standard unit in scientific, engineering, and medical literature globally.

How do I convert PSI to bar?

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To convert PSI (pounds per square inch) to bar, multiply by 0.0689476. Example: 30 PSI × 0.0689476 ≈ 2.07 bar. PSI is standard in the USA and UK; bar is widely used in Europe and most international industrial contexts.

How do I convert bar to PSI?

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To convert bar to PSI, multiply by 14.5038. Example: 2 bar × 14.5038 ≈ 29.01 PSI. This conversion is used whenever a European bar-rated specification needs to be communicated in US or UK PSI terms, or vice versa.

What is the difference between gauge pressure and absolute pressure?

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Absolute pressure is measured relative to a perfect vacuum (0 Pa). Gauge pressure is measured relative to ambient atmospheric pressure — a gauge reading of 0 means the system is at atmospheric pressure, not a vacuum. To convert gauge to absolute pressure, add approximately 101.325 kPa (14.696 PSI) at sea level. Most tyre and hydraulic gauges display gauge pressure (psig / barg), while scientific and thermodynamic calculations use absolute pressure (psia / bara / kPa abs).

What pressure unit is used for blood pressure?

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Millimeters of mercury (mmHg) is the universal clinical standard for blood pressure measurement. Normal resting blood pressure is defined as 120/80 mmHg. Despite the SI system designating kPa as the preferred unit, mmHg remains dominant in medical practice worldwide including in the USA, UK, EU, India, China, and Japan because of established clinical reference ranges.

How do I convert mmHg to kPa?

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To convert mmHg to kilopascal (kPa), multiply by 0.133322. Example: 120 mmHg (systolic blood pressure) × 0.133322 ≈ 16.0 kPa. This conversion is used in clinical research, anaesthesia records, and international medical device specifications.

How do I convert pascal to PSI?

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To convert pascal (Pa) to PSI, multiply by 0.000145038. Because one pascal is a very small unit, most practical engineering uses kPa or MPa. Example: 100,000 Pa (= 1 bar) × 0.000145038 ≈ 14.504 PSI.

What pressure unit is used in weather forecasting?

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Atmospheric pressure in weather reports is expressed in hectopascals (hPa), which are identical to millibars (mbar). Standard sea-level atmospheric pressure is 1013.25 hPa. The USA also uses inches of mercury (inHg) for aviation and some weather broadcasts. Most of the rest of the world uses hPa exclusively.

How do I convert atm to pascal?

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To convert standard atmospheres (atm) to pascals, multiply by 101,325 (exact). Example: 2 atm = 202,650 Pa = 202.65 kPa. Atmospheres are used in chemistry (gas law calculations), diving depth calculations, and some older scientific literature.

What tyre pressure unit should I use?

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The unit depends on your country and vehicle handbook. USA and UK: PSI is most common (typical car tyre: 30–35 PSI). Continental Europe and Japan: bar (typical: 2.0–2.5 bar). Australia and other metric countries: kPa (typical: 200–250 kPa). All three express the same physical pressure — this converter handles all three. Always refer to your vehicle's specified pressure, not a generic recommendation.

Is this pressure converter accurate for engineering applications?

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Yes. Conversion factors are based on exact SI definitions and NIST/ISO reference values. The tool is accurate for engineering calculations, scientific work, tyre and hydraulic pressure checks, and medical reference conversions. For safety-critical applications (pressure vessel design, medical equipment calibration), always verify against certified standards and consult a qualified engineer.

Can I use this converter globally?

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Yes. This pressure converter supports all units used across the USA, UK, EU, India, Japan, Australia, UAE, and other regions. Whether you need PSI for US HVAC specifications, bar for European industrial equipment, kPa for Australian tyre guidelines, or mmHg for medical reference, this tool covers every major pressure unit with ISO-accurate precision.

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