Pressure Converter
Convert pressure units instantly—Pa, kPa, bar, PSI, atm and more. Enter a value, choose units, and get accurate results in seconds. Ideal for tire pressure, compressors, HVAC, engineering, weather readings, and technical documentation. Free, fast, and easy to use.
Pressure Converter
The Pressure Converter converts between 19 pressure units spanning SI metric, bar-based, atmosphere-based, fluid column manometric, and imperial/US customary systems. Select the From and To units, enter the value, and click Convert. Results are displayed immediately.
Pressure units vary widely by industry and country. Tyre pressure is measured in PSI in the United States, bar in Europe, and kPa in Australia and Canada. Blood pressure is universally measured in mmHg. Weather stations use mbar (millibar) or hPa (hectopascal). Engineering uses Pa, kPa, MPa, and bar. Understanding which unit applies to your context — and whether you need gauge or absolute pressure — determines whether the converted value is correct.
How to use the Pressure Converter
- Enter the pressure value to convert.
- Select the From unit — the unit your value is currently in (e.g. PSI, bar, kPa).
- Select the To unit — the unit you want to convert to.
- Click Convert. The result is displayed immediately.
- To convert to additional units, change the To dropdown and click Convert again.
Gauge pressure vs absolute pressure — the critical distinction
The most important concept for correct pressure conversion is the difference between gauge pressure and absolute pressure. Both measure pressure, but they use different reference points:
Absolute pressure
Absolute pressure is measured relative to a perfect vacuum (0 pressure). It always has a positive value. Standard atmospheric pressure at sea level is 101,325 Pa (approximately 14.696 PSI or 1.01325 bar) in absolute terms. Used in scientific work, gas laws, and specifications where the actual total pressure matters.
Gauge pressure
Gauge pressure is measured relative to the current atmospheric pressure. It shows how much pressure exceeds (or is below) atmospheric. A car tire with an absolute pressure of 340 kPa has a gauge pressure of approximately 240 kPa (340 - 100). Most everyday pressure instruments — tire gauges, compressor gauges, blood pressure monitors — display gauge pressure. A reading of 0 PSI on a tire gauge does not mean the tire is in a vacuum — it means the tire pressure equals atmospheric pressure.
When comparing tire pressures: a gauge reading of 35 PSI means 35 PSI above atmospheric (gauge) = approximately 35 + 14.7 = 49.7 PSI absolute = approximately 3.42 bar absolute. For everyday tire inflation and compressor work, gauge pressure readings can be converted directly between PSI, bar, and kPa without worrying about atmospheric pressure — the gauge reference cancels out. Problems arise when mixing gauge and absolute values: a vacuum system specified in absolute pressure cannot be directly compared to a gauge reading without accounting for the atmospheric baseline.
All 19 units — conversion factors and contexts
| Unit | In pascals (Pa) | Typical context |
| SI / metric units | ||
| Pascal (Pa) | 1 Pa | The SI base unit of pressure. 1 Pa = 1 newton per square meter (N/m²). Atmospheric pressure at sea level is approximately 101,325 Pa. Used in engineering specifications, scientific work, and building physics (wind load, HVAC). |
| Kilopascal (kPa) | 1,000 Pa | Tire pressure (in metric countries), blood pressure (medical), gas line pressure, weather forecasting (atmospheric pressure ≈ 101.325 kPa). Tire pressure of 2.4 bar = 240 kPa = approximately 35 PSI. |
| Megapascal (MPa) | 1,000,000 Pa | High-pressure engineering: hydraulic systems, pipe pressure ratings, concrete compressive strength, pressure vessel specifications, tensile and compressive stress in materials engineering. 1 MPa = 10 bar = approximately 145 PSI. |
| Newton/sq. metre | 1 Pa | Equivalent to the pascal. The same quantity expressed using fundamental SI force and area units rather than the derived pascal name. Appears in some engineering calculations and standards. |
| Bar-based units | ||
| Bar | 100,000 Pa | Widely used in Europe and internationally for tire pressure, gas cylinder ratings, pump specifications, and industrial equipment. 1 bar ≈ 1 atm (slightly less: 1 atm = 1.01325 bar). Tire pressure of 2.2 bar is typical for passenger car front tires. |
| Millibar (mbar) | 100 Pa | Meteorology and weather forecasting. Atmospheric pressure is reported in millibars on many weather stations and forecasting systems. Standard atmospheric pressure = 1,013.25 mbar. Also used for low-pressure system specifications (HVAC, cleanrooms). |
| Decibar | 10,000 Pa | Oceanography: pressure at depth in the ocean. 1 decibar corresponds approximately to the pressure increase at 1 meter of water depth. Water depth in meters and pressure in decibars are numerically very close (1 dbar ≈ 1 meter depth), which makes decibars convenient for oceanographic data. |
| Atmosphere-based units | ||
| Atmosphere (normal, atm) | 101,325 Pa | Standard atmosphere: the reference atmospheric pressure at sea level defined by international convention. 1 atm = 101,325 Pa = 1.01325 bar = 14.696 PSI = 760 mmHg. Used as a reference for gas laws (STP = Standard Temperature and Pressure), dive tables, and pressure comparisons. |
| Atmosphere (technical, at) | 98,066.5 Pa | The technical atmosphere: 1 at = 1 kgf/cm² = 98,066.5 Pa. An older unit used in German engineering standards and some European industrial specifications. Slightly less than the standard atmosphere (atm). Now largely superseded by bar and Pa in modern standards. |
| Torr (mmHg, 0°C) | 133.322 Pa | Named after Evangelista Torricelli (inventor of the barometer). 1 Torr = 1/760 atm = 133.322 Pa. Used in vacuum engineering (vacuum levels below atmospheric), medical blood pressure (traditional mmHg = Torr), and some laboratory equipment. 1 Torr is almost exactly equal to 1 mmHg. |
| Fluid column units (manometric) | ||
| Millimeter of mercury (mmHg) | 133.322 Pa | Blood pressure measurement (systolic/diastolic, e.g. 120/80 mmHg), vacuum engineering, and traditional barometry. 1 mmHg = 1 Torr. The standard blood pressure measurement unit in clinical practice worldwide. |
| Centimeter of mercury (cmHg) | 1,333.22 Pa | Similar applications to mmHg but at a 10x larger scale. Less commonly used than mmHg. Some older pressure gauges and manometers use cmHg. |
| Centimeter of water (4°C) | 98.0638 Pa | Low-pressure measurements: HVAC duct pressure, respiratory physiology (peak expiratory flow resistance), water column pressure in plumbing, and medical ventilator settings. Water column units are used when pressures are too small for mercury column measurement to be convenient. |
| Imperial / US customary units | ||
| Pound-force per sq. inch (PSI) | 6,894.76 Pa | The most common pressure unit in the United States. Tyre pressure, hydraulic systems, compressors, boilers, and pipe fittings in the US market. Standard car tyre pressure is approximately 30–36 PSI. 1 PSI = 0.0689 bar = 6.895 kPa. |
| Pound-force per sq. foot (lbf/ft²) | 47.880 Pa | US structural engineering and wind load calculations. Wind pressure on building facades in US codes is specified in lb/ft². Rarely used for fluid pressures — PSI is preferred for those applications. |
| Poundal per sq. foot | 1.4882 Pa | A rarely used US engineering unit employing the poundal (force unit) rather than pound-force. 1 poundal = the force needed to accelerate 1 lb mass at 1 ft/s². Encountered in some older US engineering texts. For practical purposes, use PSI or lbf/ft². |
| Kip per sq. inch (ksi) | 6,894,757 Pa | Structural and civil engineering in the US: steel strength, concrete compressive strength, bolt tension, foundation bearing capacity. 1 kip = 1,000 pound-force. 1 ksi = 1,000 PSI = approximately 6.895 MPa. Common in US structural steel and concrete design codes. |
| Kgf per sq. centimeter (kgf/cm²) | 98,066.5 Pa | Equivalent to the technical atmosphere (1 at = 1 kgf/cm²). Used in some older European and Asian engineering standards, hydraulic equipment specifications from non-SI countries, and some legacy pressure gauges. Approximately equal to 1 bar or 14.22 PSI. |
| Kgf per sq. meter (kgf/m²) | 9.80665 Pa | Very low pressure differences, such as air resistance in HVAC ducts, building thermal calculations, and some European structural load specifications. 1 kgf/m² ≈ 9.807 Pa. Similar in scale to cmH₂O. |
Practical pressure reference — common values in four units
The table below shows familiar pressure values across PSI, bar, kPa, and mmHg — useful for verifying conversion results and building intuition for pressure magnitudes:
| Pressure reference | PSI | bar | kPa | mmHg |
| Standard atmosphere (sea level) | 14.696 | 1.01325 | 101.325 | 760 |
| Typical car tire (front) | 32–36 | 2.2–2.5 | 220–250 | 1,654–1,875 |
| Typical car tire (rear) | 33–38 | 2.3–2.6 | 230–260 | 1,727–1,952 |
| Bicycle tire (road) | 80–130 | 5.5–9.0 | 550–900 | 4,129–6,757 |
| Blood pressure (normal systolic) | ~2.3 | ~0.16 | ~16 | 120 |
| Blood pressure (normal diastolic) | ~1.6 | ~0.11 | ~11 | 80 |
| HVAC duct (typical) | ~0.001–0.015 | ~0.00007–0.001 | ~0.01–0.1 | ~0.1–1 |
| Scuba tank (full) | ~3,000 | ~207 | ~20,700 | ~155,500 |
| Hydraulic system (industrial) | ~2,000–5,000 | ~138–345 | ~13,800–34,500 | ~103,500–258,900 |
Tire pressure matters for safety, fuel economy, and tire wear. Under-inflated tires increase rolling resistance, heat build-up, and blowout risk; over-inflated tires reduce grip and cause uneven wear. Always check your vehicle's recommended pressure — found on the driver's door jamb sticker or owner's manual, not the maximum pressure printed on the tire sidewall. Recommended pressure is in PSI in the US, bar in most of Europe, and kPa in Australia and Canada. 2.4 bar = 240 kPa = approximately 35 PSI (close enough for most passenger cars; check your specific vehicle).
Usage limits
| Account type | Daily conversions |
| Guest | 25 per day |
| Registered | 100 per day |
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Frequently asked questions
How do I convert PSI to bar?
Divide PSI by 14.5038 to get bar. Or multiply by 0.0689476. Examples: 30 PSI / 14.5038 = 2.069 bar; 35 PSI / 14.5038 = 2.413 bar; 2.4 bar x 14.5038 = 34.81 PSI. Quick approximation: PSI / 14.5 = bar; bar x 14.5 = PSI. For tire pressure: 2.2 bar ≈ 32 PSI; 2.4 bar ≈ 35 PSI; 2.6 bar ≈ 38 PSI.
How do I convert PSI to kPa?
Multiply PSI by 6.89476 to get kPa. Examples: 30 PSI x 6.89476 = 206.8 kPa; 35 PSI x 6.89476 = 241.3 kPa. To convert kPa to PSI: divide by 6.89476 (or multiply by 0.14504). Standard car tire pressure of 240 kPa ≈ 35 PSI ≈ 2.4 bar.
What is the difference between PSI and bar?
Both are pressure units — PSI (pounds-force per square inch) is the standard in the United States; bar is widely used in Europe and internationally. 1 bar = 14.5038 PSI; 1 PSI = 0.0689 bar. They measure the same physical quantity (force per unit area) with different unit scales. For tire pressure, a US tire inflated to 35 PSI contains the same pressure as a European tire inflated to 2.41 bar.
What is gauge pressure vs absolute pressure?
Gauge pressure is measured relative to the current atmospheric pressure (approximately 14.7 PSI or 1.013 bar at sea level). It shows how much the pressure exceeds atmospheric. Most everyday gauges — tire gauges, compressor gauges — display gauge pressure. Absolute pressure is measured relative to a perfect vacuum: absolute pressure = gauge pressure + atmospheric pressure. A tire at 35 PSI gauge pressure has an absolute pressure of approximately 35 + 14.7 = 49.7 PSI absolute. For direct conversion between gauge pressures in different units (PSI to bar), no adjustment for atmospheric is needed — the gauge reference cancels out.
What is a Torr and how does it relate to mmHg?
A Torr is a pressure unit named after Evangelista Torricelli, inventor of the mercury barometer. 1 Torr = 1/760 of a standard atmosphere = 133.322 Pa. It is almost exactly equal to 1 millimeter of mercury (mmHg) — the two are often used interchangeably, though they differ by less than 0.000016%. Torr is used in vacuum engineering (expressing pressures below atmospheric) and in some laboratory equipment. mmHg is the universal unit for blood pressure in clinical medicine (e.g. 120/80 mmHg for a normal reading).
What does atmospheric pressure mean and why does it vary?
Atmospheric pressure is the force per unit area exerted by the weight of the air column above a given point. At sea level, standard atmospheric pressure is 101,325 Pa = 1 atm = 1.01325 bar = 14.696 PSI = 760 mmHg = 1,013.25 mbar. It varies with altitude (decreasing as altitude increases — approximately -12 Pa per meter at sea level), weather systems (high pressure systems up to ~1,040 mbar; low pressure systems down to ~960 mbar), and temperature. Weather stations report atmospheric pressure corrected to sea level so that readings from different elevations can be compared.
What is a ksi and where is it used?
Ksi (kilopond-force per square inch) = 1,000 PSI = approximately 6.895 MPa. It is used in US structural and civil engineering for material strength specifications: the compressive strength of concrete (typically 3,000–8,000 PSI = 3–8 ksi), the yield strength of structural steel (typically 36–100 ksi), and bearing capacity of foundations. Engineers in the US work in ksi rather than MPa because design codes, material specifications, and structural steel tables are published in ksi. 1 ksi ≈ 6.895 MPa.
Is the Pressure Converter free?
Yes. The converter is free within the daily usage limits shown above. Guest users can perform 25 conversions per day without creating an account. Registering a free ToolsPiNG account increases the daily limit to 100 conversions per day.