Atmosphere to Pascal Converter
Convert atmosphere pascal between units instantly. Includes conversion tables, common equivalents, and calculation formulas.
Atmosphere to Pascal Converter
Calculator
Adjust values & calculateEnter your values below. Every result is computed in your browser โ no data is sent to any server.
Formula: Pa = atm x 101325 | 1 bar = 100000 Pa | 1 PSI = 6894.76 Pa
Worked example โ 32 PSI = 220,632 Pa = 2.21 bar
Formula
Pa = atm x 101325 | 1 bar = 100000 Pa | 1 PSI = 6894.76 Pa
One standard atmosphere equals exactly 101,325 pascals. All pressure conversions use the pascal as the base SI unit. Key relationships: 1 bar = 100,000 Pa, 1 PSI = 6,894.76 Pa, 1 mmHg (torr) = 133.322 Pa, 1 inHg = 3,386.39 Pa. The pascal is defined as one newton per square meter.
Worked Examples
Example 1: Tire Pressure Conversion
Problem:Convert 32 PSI tire pressure to pascals and bar.
Solution:Pascals: 32 x 6,894.76 = 220,632.32 Pa Kilopascals: 220,632.32 / 1000 = 220.63 kPa Bar: 220,632.32 / 100,000 = 2.2063 bar Atmospheres: 220,632.32 / 101,325 = 2.178 atm
Result:32 PSI = 220,632 Pa = 2.21 bar
Example 2: Weather Pressure
Problem:A barometer reads 760 mmHg. What is this in pascals and atmospheres?
Solution:Pascals: 760 x 133.322 = 101,324.72 Pa Atmospheres: 101,324.72 / 101,325 = 1.0000 atm Bar: 101,324.72 / 100,000 = 1.0132 bar
Result:760 mmHg = 101,325 Pa = 1.0 atm (standard pressure)
Frequently Asked Questions
How many pascals are in one atmosphere?
One standard atmosphere (atm) equals exactly 101,325 pascals (Pa) or 101.325 kilopascals (kPa). This value was defined by the International Union of Pure and Applied Chemistry (IUPAC) based on the average atmospheric pressure at sea level and 15 degrees Celsius. The pascal is the SI unit of pressure defined as one newton per square meter. Standard atmospheric pressure is used as a reference in chemistry, aviation, and meteorology.
What is a pascal and what is it used for?
A pascal (Pa) is the SI unit of pressure equal to one newton of force per square meter of area. Named after French mathematician Blaise Pascal, it is used in engineering, physics, meteorology, and material science. Because one pascal is a very small pressure (about 0.000145 psi), kilopascals (kPa) and megapascals (MPa) are more commonly used in practice. Tire pressure, blood pressure, and weather reports often use related units like bar, mmHg, or millibar.
How do I convert between PSI and atmospheres?
One atmosphere equals approximately 14.696 PSI (pounds per square inch). To convert PSI to atmospheres, divide by 14.696. To convert atmospheres to PSI, multiply by 14.696. For example, a tire inflated to 35 PSI has a pressure of about 2.38 atmospheres (35 / 14.696). PSI is the standard pressure unit in the United States for tires, compressed gas, and hydraulic systems, while atmospheres are more common in scientific contexts.
What is the difference between gauge pressure and absolute pressure?
Absolute pressure measures pressure relative to a perfect vacuum (zero pressure), while gauge pressure measures pressure relative to atmospheric pressure. A tire gauge reading of 35 PSI (gauge) actually means 49.7 PSI absolute (35 + 14.7 atmospheric). In scientific calculations, absolute pressure is usually required. Weather barometers measure absolute atmospheric pressure. This converter works with absolute pressure values by default.
Is one bar the same as one atmosphere?
No, and the gap is small enough to be dangerous. A bar is defined as exactly 100,000 Pa, while a standard atmosphere is exactly 101,325 Pa, so 1 bar is 0.98692 atm and 1 atm is 1.01325 bar, a difference of about 1.3%. The bar was adopted precisely because it is a round SI number, and thermodynamic standard states in chemistry are now referenced to 100 kPa rather than to the atmosphere, so tabulated data can differ depending on which convention a source used.
What is the difference between a torr and a millimetre of mercury?
They come from different definitions yet agree almost exactly. The torr is defined as one seven-hundred-and-sixtieth of a standard atmosphere, 101,325 / 760 = 133.3224 Pa. The millimetre of mercury is defined physically, as the pressure from a 1 mm column of mercury at density 13,595.1 kg per cubic metre under standard gravity: 0.001 x 13,595.1 x 9.80665 = 133.3224 Pa. The two agree to about one part in ten million, so vacuum and clinical work treat them as interchangeable.
Why do aviation altimeters use inches of mercury?
It is a barometric convention inherited from mercury barometers, where an inch of mercury is 25.4 mm and therefore 3,386.39 Pa. Standard sea-level pressure of 101,325 Pa comes out as 29.92 inHg, the familiar altimeter setting. Regions using metric units broadcast the same quantity in hectopascals, where 1 hPa equals 1 millibar, so standard pressure is 1,013.25 hPa. Setting the wrong one, or the wrong regional value, offsets indicated altitude, which is why the setting is read back on every clearance.
How much pressure does a column of water or another liquid add?
Hydrostatic pressure is p = rho x g x h, with density in kilograms per cubic metre, standard gravity 9.80665 m/s2, and depth in metres. Fresh water at 1,000 kg/m3 gives 1,000 x 9.80665 x 10 = 98,067 Pa for ten metres, close to one atmosphere. That is the rule of thumb divers use: roughly one extra atmosphere of absolute pressure per ten metres of depth, so at 30 m a diver is at about four atmospheres absolute counting the air above the surface.
Where does the conversion factor 6,894.76 for PSI come from?
It is built from the definitions of the pound-force and the inch. One pound-force is 4.4482216152605 newtons and one inch is exactly 0.0254 metres, so a square inch is 0.00064516 square metres. Dividing gives 4.4482216 / 0.00064516 = 6,894.757 Pa per PSI. Because both inputs are exact by definition, the factor is exact too, and any rounding you see is only in how many digits a table chose to print rather than genuine measurement uncertainty.
How quickly does atmospheric pressure fall with altitude?
Near sea level the drop is about 12 pascals per metre climbed, which follows from p = rho x g x h using standard air density of roughly 1.225 kg/m3: 1.225 x 9.80665 is close to 12.0 Pa per metre. The fall is not linear, though, because the air itself thins as pressure drops, so the decline is roughly exponential and pressure approximately halves every 5.5 km. That is why a sealed bag inflates in an aircraft cabin and why boiling point falls at altitude.
References
Background & Theory
1 standard atmosphere = 101,325 pascals exactly = 760 torr = 1.01325 bar. The atmosphere is a defined constant, not an average of real measurements, which is why the figure has no uncertainty attached to it.
Conversion reference table
| Conversion | Equivalent | Exact or rounded? |
|---|---|---|
| 1 standard atmosphere | 101,325 pascals | Exact by definition |
| 1 standard atmosphere | 760 torr | Exact by definition |
| 1 standard atmosphere | 1.01325 bar = 1,013.25 millibar | Exact |
| 1 standard atmosphere | 14.6959488 psi | Derived, rounded |
| 1 standard atmosphere | 29.9212598 inches of mercury | Derived, rounded |
| 1 torr | 101325/760 = 133.322368 pascals | Exact fraction, rounded |
| 1 mmHg (conventional) | 133.322387415 pascals | Exact by convention |
The torr and the conventional millimetre of mercury are defined slightly differently and differ by about one part in seven million, which matters only in high-vacuum metrology; below that level of precision they are used interchangeably. Real sea-level pressure varies roughly between 980 and 1,040 hPa with the weather, so the standard atmosphere is a reference point rather than a description of today.
Reviewed for accuracy by Manoj Kumar, Mathematics Educator ยท Editorial policy
Related Calculators
๐งฎBar to Pascal Converter
Calculate bar to pascal converter with inputs, formulas, and instant results.
๐งฎPascal to Torr Converter
Calculate pascal to torr converter with inputs, formulas, and instant results.
๐งฎKilopascal to PSI Converter
Calculate kilo pascal to psiconverter with inputs, formulas, and instant results.
๐งฎTorque Unit Converter
Calculate torque unit converter with inputs, formulas, and instant results.
๐งฎElectrical Resistance Converter (ฮฉ, kฮฉ, Mฮฉ)
Calculate electrical resistance unit converter with inputs, formulas, and instant results.
๐งฎTime Unit Converter
Calculate time unit converter with inputs, formulas, and instant results.
๐งฎArea Converter
Calculate area converter with inputs, formulas, and instant results.
๐งฎAresto Hectares Converter
Calculate aresto hectares converter with inputs, formulas, and instant results.