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Pressure Conversion
Tool Description
Pressure Conversion is an online pressure unit converter with daily free quota — no installation, no registration, ready to use. It supports mutual conversion between 11 pressure units, including pascal (Pa), hectopascal (hPa), kilopascal (kPa), megapascal (MPa), bar, millibar (mbar), standard atmosphere (atm), millimeter of mercury (mmHg), inch of mercury (inHg), pound per square inch (psi), and kilogram-force per square centimeter (kgf/cm²). Enter any value and unit to instantly view results in all units. All calculations run entirely in your browser, 100% privacy protected. Whether for physics learning, weather analysis, engineering design, tire pressure, or medical blood pressure, its easy to handle — start using it free with results comparable to professional engineering software.
How to Use
- Enter a value
Enter a value: Enter the value to convert in the input box. Both integers and decimals are supported, e.g.
1000,101.325 - Select source unit
Select source unit: Choose the pressure unit of the current value from the dropdown (Pa/
hPa/ kPa/ MPa/ bar/ mbar/ atm/ mmHg/ inHg/ psi/ kgf/cm²) - View results
View results: Click the "Convert" button or press Enter — the results area below will display the corresponding values in all units, with a copy button beside each result for convenience
Use Cases
- Weather Analysis: Hectopascal (hPa) and millibar (mbar) are commonly used for atmospheric pressure in weather forecasts — quickly convert to standard atmosphere (atm) or inch of mercury (inHg); compare typhoon central pressure in hPa with everyday pressure
- Engineering & Industry: MPa and bar are commonly used in hydraulic systems — quickly convert to psi or kgf/cm²; unit conversion in pipeline pressure testing, boiler pressure, and compressed gas cylinder scenarios
- Automotive & Tires: Tire pressure commonly uses psi (US/EU) and bar/kgf/cm² (Asia) — quickly switch between these units; convert recommended tire pressure values in vehicle manuals
Core Advantages
- Daily Free Quota
The online pressure unit converter provides free usage every day. Just open the page and use it — no account registration or software installation required
- Local & Private
All conversions run locally in your browser. Your input data is never uploaded to any server, fully protecting your privacy
- Instant Calculation
Results are calculated instantly as you type, with no waiting — all unit results are shown at a glance
- Comprehensive Units
Supports 11 pressure units including pascal, bar, atm, mmHg and psi, covering weather, engineering, medical and automotive fields
- High Precision
Uses exact mathematical computation; standard atmosphere uses the internationally recognized exact value (1 atm = 101,325 Pa) and supports decimals and extreme values
- Cross-platform
Works smoothly on desktop, mobile and tablet. The page is responsive and lets you convert units anytime, anywhere
Pressure Unit Conversion Relationships
The following shows the conversion relationships between pressure units, with pascal (Pa) as the base unit:
| Unit Name | Abbr | Conversion | Equivalent Pascals |
|---|---|---|---|
| Pascal | Pa | 1 Pa = 1 N/m² | 1 |
| Hectopascal | hPa | 1 hPa = 100 Pa | 100 |
| Kilopascal | kPa | 1 kPa = 10³ Pa | 1,000 |
| Megapascal | MPa | 1 MPa = 10⁶ Pa | 1,000,000 |
| Bar | bar | 1 bar = 10⁵ Pa | 100,000 |
| Millibar | mbar | 1 mbar = 100 Pa | 100 |
| Standard Atmosphere | atm | 1 atm = 101,325 Pa | 101,325 |
| Millimeter of Mercury | mmHg | 1 mmHg ≈ 133.322 Pa | 133.322 |
| Inch of Mercury | inHg | 1 inHg ≈ 3,386.39 Pa | 3,386.39 |
| Pound per Square Inch | psi | 1 psi ≈ 6,894.76 Pa | 6,894.76 |
| Kilogram-force per Square Centimeter | kgf/cm² | 1 kgf/cm² = 98,066.5 Pa | 98,066.5 |
Common Pressure Units by Field
Different industries and disciplines use different pressure units. Understanding their applications helps you better use the conversion tool.
The table below lists the most common application fields and typical examples for each pressure unit:
| Pressure Unit | Application Field | Typical Example |
|---|---|---|
| Pa, kPa | Physics, Engineering | Stress and pressure calculations in material mechanics |
| hPa, mbar | Meteorology | Barometric pressure forecasts, typhoon central pressure |
| MPa, bar | Hydraulics, Industry | Hydraulic press pressure, pipeline pressure ratings |
| mmHg | Medical, Meteorology | Blood pressure measurement, barometer readings |
| atm | Physics, Chemistry | Standard temperature and pressure (STP) reference |
| psi | Automotive, Aviation | Tire pressure, aircraft cabin pressure |
FAQ
1 standard atmosphere (atm) = 101,325 pascals (Pa), i.e. 101.325 kPa. Standard atmosphere is defined as the pressure exerted by a mercury column 760 mm high at sea level and 0°C, with a mercury density of 13.5951 g/cm³. In everyday terms, standard atmosphere is approximately 1.01325 bar or 14.696 psi.
1 bar = 100,000 Pa = 100 kPa = 0.1 MPa. Bar is a very commonly used unit in engineering because its magnitude is close to standard atmospheric pressure (1 bar ≈ 0.9869 atm), making it convenient for everyday use. In meteorology, millibar (mbar) is commonly used: 1 mbar = 1 hPa = 100 Pa.
Common tire pressure unit conversions: 1 bar ≈ 14.504 psi, 1 kgf/cm² ≈ 14.223 psi, and 1 bar ≈ 1.0197 kgf/cm² (they are very close). For example, a common recommended car tire pressure of 2.2 bar equals approximately 31.9 psi or 2.24 kgf/cm². US and European vehicles typically use psi, while Japanese, Korean, and Chinese vehicles often use bar or kgf/cm².
mmHg (millimeter of mercury) is the standard unit for blood pressure measurement in medicine, representing the height of a mercury column. A normal resting adult blood pressure is approximately 120/80 mmHg (systolic/diastolic), which converts to approximately 16.0/10.7 kPa. 1 mmHg ≈ 133.322 Pa ≈ 0.133 kPa. Although international standards recommend using kPa, mmHg is still widely used in clinical practice.
No. All conversion calculations run entirely in your browser using pure JavaScript math. Your input data never leaves your device.
This tool uses JavaScript double-precision floating-point numbers (64-bit IEEE 754) for calculations, which is sufficiently accurate for the vast majority of everyday scenarios. Standard atmosphere uses the internationally recognized exact value (1 atm = 101,325 Pa). Decimal portions are capped at 6 significant decimal places, and excessively long decimals are automatically truncated. For extremely large or small values, there may be minor errors due to floating-point precision limitations, but this has virtually no practical impact.
11 units in total. Including pascal (Pa), hectopascal (hPa), kilopascal (kPa), megapascal (MPa), bar, mbar, standard atmosphere (atm), mmHg, inch of mercury (inHg), psi and kgf/cm². Enter any unit and convert to all the others at once.
It depends on the context. "Standard atmosphere (atm)" is often mentioned in weather and daily life, while bar (1 bar ≈ 0.9869 atm, close to but slightly different from 1 atm) is more common in engineering and industry. Both are pressure units and the tool converts freely between them, Pa and psi.
History and clinical habit. mmHg directly corresponds to mercury sphygmomanometer readings and is familiar to doctors; clinical values (e.g. 120/80) are easy to read and remember. Although international standards recommend kPa, mmHg remains widely used in healthcare, and this tool supports conversion between both.
Click the copy button next to each result. A one-click copy button is provided beside every unit result — click it and the value goes to your clipboard, ready to paste into documents, spreadsheets or chats.
Yes. The page is responsive and works on phones, tablets and desktop browsers. Input and result-copying work on mobile too.
Free usage is provided every day, so daily use costs nothing. We prepare a daily free quota for every user, which is enough for basic pressure conversion. Just open the page and use it; if you need more frequent or professional use, a membership unlocks more benefits.
Content last updated：2026-07-16
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