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Pressure Converter

Enter a value to instantly convert between pressure units.

Pressure conversions are most commonly needed for tire inflation (PSI vs. bar vs. kPa), weather reports (atmospheric pressure in different units depending on the country), and a range of technical and scientific contexts — scuba diving, cooking with pressure cookers, and engineering specifications. Because pressure units originate from very different physical reference points (a column of mercury, a force per unit area, or a fraction of atmospheric pressure), the conversion factors between them don't follow an obvious pattern, making a reliable converter especially useful here.

Precision4 dp

1 Pound per Sq. Inch = 0.0689 Bar

Key Formulas

Pound per Sq. Inch → Bar

bar = psi × 0.0689476

Bar → Pound per Sq. Inch

psi = bar × 14.5038

Atmosphere → Pound per Sq. Inch

psi = atm × 14.6959

Pound per Sq. Inch → Atmosphere

atm = psi × 0.068046

Popular Conversions

Kilopascal to Pound per Sq. Inch Bar to Pound per Sq. Inch Pound per Sq. Inch to Kilopascal Pound per Sq. Inch to Bar Pound per Sq. Inch to Atmosphere Atmosphere to Pound per Sq. Inch

All Pressure Conversions

Kilopascal to Pound per Sq. Inch Bar to Pound per Sq. Inch Pound per Sq. Inch to Kilopascal Pound per Sq. Inch to Bar Pound per Sq. Inch to Atmosphere Atmosphere to Pound per Sq. Inch Pascal to Kilopascal Pascal to Megapascal Pascal to Bar Pascal to Millibar Pascal to Pound per Sq. Inch Pascal to Atmosphere Pascal to Torr Pascal to mmHg Kilopascal to Pascal Kilopascal to Megapascal Kilopascal to Bar Kilopascal to Millibar Kilopascal to Atmosphere Kilopascal to Torr Kilopascal to mmHg Megapascal to Pascal Megapascal to Kilopascal Megapascal to Bar Megapascal to Millibar Megapascal to Pound per Sq. Inch Megapascal to Atmosphere Megapascal to Torr Megapascal to mmHg Bar to Pascal Bar to Kilopascal Bar to Megapascal Bar to Millibar Bar to Atmosphere Bar to Torr Bar to mmHg Millibar to Pascal Millibar to Kilopascal Millibar to Megapascal Millibar to Bar Millibar to Pound per Sq. Inch Millibar to Atmosphere Millibar to Torr Millibar to mmHg Pound per Sq. Inch to Pascal Pound per Sq. Inch to Megapascal Pound per Sq. Inch to Millibar Pound per Sq. Inch to Torr Pound per Sq. Inch to mmHg Atmosphere to Pascal Atmosphere to Kilopascal Atmosphere to Megapascal Atmosphere to Bar Atmosphere to Millibar Atmosphere to Torr Atmosphere to mmHg Torr to Pascal Torr to Kilopascal Torr to Megapascal Torr to Bar Torr to Millibar Torr to Pound per Sq. Inch Torr to Atmosphere Torr to mmHg mmHg to Pascal mmHg to Kilopascal mmHg to Megapascal mmHg to Bar mmHg to Millibar mmHg to Pound per Sq. Inch mmHg to Atmosphere mmHg to Torr

About Pressure Conversions

History & Background

The pascal (Pa), the SI unit of pressure, is defined simply as one newton per square meter — a clean derived unit from force and area. PSI (pounds per square inch) follows the same logic using imperial force and area units. The bar, widely used in Europe and convenient because it's very close to standard atmospheric pressure (1 bar ≈ 0.987 atm), was introduced in the early 20th century as a practical round-number unit for meteorology and engineering. Older units like the atmosphere (atm) and millimeters/inches of mercury (mmHg, inHg) originate from early barometers, which measured air pressure by how high it pushed a column of mercury — units that persist today in weather reporting and medical blood pressure measurements (though blood pressure uses mmHg specifically, not a general pressure conversion).

How to Use This Converter

Choose your starting and target pressure units and enter a value for an instant result. For tire pressure, PSI, bar, and kPa are the most common; for weather, hPa (hectopascals, equal to millibars) and inHg are typical depending on the country. Always double-check which unit a specification uses before converting — confusing bar and PSI, for example, represents roughly a 14-fold difference in pressure.

Frequently Asked Questions

Why does my car's tire pressure sticker show a different unit than my tire gauge?

Vehicles are often sold internationally, and manufacturers print specifications in the units relevant to multiple markets — typically PSI for the US/UK and bar or kPa for Europe and elsewhere. If your gauge reads in a different unit than the sticker, convert the recommended figure to your gauge's unit before inflating, since the numeric values look similar in magnitude (e.g., '32' vs '2.2') but represent very different pressures.

What's the difference between gauge pressure and absolute pressure?

Gauge pressure is measured relative to atmospheric pressure (so a tire at 'zero' gauge pressure is actually at atmospheric pressure, about 14.7 PSI absolute), while absolute pressure is measured relative to a perfect vacuum (zero). Tire pressure gauges read gauge pressure; most pressure conversions on this site, including tire-related ones, are gauge-pressure conversions, which is the convention used in everyday contexts.

Why is 1 bar approximately equal to 1 atmosphere?

This is mostly a convenient coincidence of the bar's definition: 1 bar = 100,000 pascals, and standard atmospheric pressure is defined as 101,325 pascals — so 1 bar is about 98.7% of 1 atm. The bar was deliberately chosen as a round number close to atmospheric pressure, making it intuitive for meteorology (where pressure readings cluster around 1 bar / 1000 hPa) even though the two units aren't exactly equal.

Popular Use Cases

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