Pressure is a physical quantity that defines the force exerted per unit area, and depending on the application or our geographical location, it can be measured in different units, Bar [Bar], Pa [Pascal], Kpa [Kilopascal], and Psi [Pounds per Square Inch].
When converting between different units of pressure, having a conversion table with factors and explanations of each unit of measurement can be incredibly helpful.
This article will provide a comprehensive guide to pressure unit conversion, including a conversion table of up to 50 bar that can be downloaded.
🟩 Pressure ConversionsTo help easily convert between different units of pressure, we’ve compiled a table of pressure conversions that lists the factors for Bar, Pa, Kpa, and Psi from 0 to 50 bar, this can be found further in the article.
The below table shows the conversion factors for each:
Bar‘Bar’ was introduced by Vilhelm Bjerknes, a Norwegian meteorologist who founded the modern practice of weather forecasting, and is used as a unit of pressure that is defined as 100,000 Pascals (100 kPa). It is often used to measure pressure in mechanical engineering, building services, automobiles, and monitoring tire pressures – based on the pressure in the atmosphere, with one bar roughly equal to the pressure at sea level on a cool day.
Bar is defined as being roughly the atmospheric pressure on Earth at an altitude of 111 meters [365 feet] at 15 °C [59°F].
Some common pressure measurements that are expressed in Bar include:
The Pascal (Pa) is the SI unit of pressure. It is named after Blaise Pascal, a French mathematician, and physicist who made significant contributions to the study of fluids and pressure.
Pascal is defined as the pressure exerted by a force of one Newton per square meter [N/m²].
This means that it is a relatively small unit of pressure, and larger pressures are typically expressed in kilopascals (Kpa) or megapascals (Mpa). As shown in the table of pressure conversions, 1 Kpa is equivalent to 1,000 Pa, and 1 Mpa is equal to 1,000,000 Pa.
Some common pressure measurements that are expressed in Pascal include:
Kilopascals are typically used depending on the scale of the pressure being measured.
Pascals are the basic unit; however, they are relatively small units compared, and when measuring larger pressures, such as those found in engineering applications, kilopascals are often used instead.
One kilopascal is equal to 1,000 pascals.
🟩 Pounds per square inch [Psi]Psi (pounds per square inch or pound-force per square inch) is a unit of pressure commonly used in the United States to measure pressure in hydraulic systems, pneumatic systems, and other industrial applications and is defined as the pressure exerted by a force of one pound-force applied to an area of one square inch.
Some common pressure measurements that are expressed in Psi include:
The below table provides reference conversions for pressures from 0 bar to 50 bar | 0 pascal to 5 mln pascal | 0 Kpa to 5,000 Kpa & 0 Psi to 725 Psi
BarClick the ‘Download | Free’ button to be taken to our shop and have this emailed to you [covering 0 to 50 bar]:
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⬛ Latest Articles ⬛ AuthorThe pound per square inch (abbreviation: psi) or, more accurately, pound-force per square inch (symbol: lbf/in2),[1] is a unit of measurement of pressure or of stress based on avoirdupois units. It is the pressure resulting from a force with magnitude of one pound-force applied to an area of one square inch. In SI units, 1 psi is approximately 6,895 pascals.
The pound per square inch absolute (psia) is used to make it clear that the pressure is relative to a vacuum rather than the ambient atmospheric pressure. Since atmospheric pressure at sea level is around 14.7 psi (101 kilopascals), this will be added to any pressure reading made in air at sea level. The converse is pound per square inch gauge (psig), indicating that the pressure is relative to atmospheric pressure. For example, a bicycle tire pumped up to 65 psig in a local atmospheric pressure at sea level (14.7 psi) will have a pressure of 79.7 psia (14.7 psi + 65 psi).[2][3] When gauge pressure is referenced to something other than ambient atmospheric pressure, then the unit is pound per square inch differential (psid).
Multiples
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The kilopound per square inch (ksi) is a scaled unit derived from psi, equivalent to a thousand psi (1000 lbf/in2).
ksi are not widely used for gas pressures. They are mostly used in materials science, where the tensile strength of a material is measured as a large number of psi.[4]
The conversion in SI units is 1 ksi = 6.895 MPa, or 1 MPa = 0.145 ksi.
The megapound per square inch (Mpsi) is another multiple equal to a million psi. It is used in mechanics for the elastic modulus of materials, especially for metals.[5]
The conversion in SI units is 1 Mpsi = 6.895 GPa, or 1 GPa = 0.145 Mpsi.
Magnitude
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Conversions
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The conversions to and from SI are computed from exact definitions but result in a repeating decimal. [6][7]
P Pa = P PSI × ( 0.45359237 kg × 9.80665 m / s 2 ) / lbf ( 0.0254 m / in ) 2 {\displaystyle P_{\text{Pa}}=P_{\text{PSI}}\times {\frac {(0.45359237~{\text{kg}}\times 9.80665~\mathrm {m/s^{2}} )/{\text{lbf}}}{(0.0254~{\text{m}}/{\text{in}})^{2}}}}
P PSI = P Pa × ( 0.0254 m / in ) 2 ( 0.45359237 kg × 9.80665 m / s 2 ) / lbf {\displaystyle P_{\text{PSI}}=P_{\text{Pa}}\times {\frac {(0.0254~{\text{m}}/{\text{in}})^{2}}{(0.45359237~{\text{kg}}\times 9.80665~\mathrm {m/s^{2}} )/{\text{lbf}}}}}
As the pascal is a very small unit relative to industrial pressures, the kilopascal is commonly used. 1000 kPa ≈ 145 lbf/in2.
Approximate conversions (rounded to some arbitrary number of digits, except when denoted by "≡") are shown in the following table.
Pressure units Pascal Bar Technical atmosphere Standard atmosphere Torr Pound per square inch (Pa) (bar) (at) (atm) (Torr) (lbf/in2) 1 Pa — 1 Pa = 10−5 bar 1 Pa = 1.0197×
10−5 at 1 Pa = 9.8692×
10−6 atm 1 Pa = 7.5006×
10−3 Torr 1 Pa = 0.000145
037
737
730
lbf/in2 1 bar 105 — = 1.0197 = 0.98692
= 750.06 = 14.503773
773
022
1 at 98066
.5 0.980665
— 0.967841
105
3541
735.5592401
14.223343
307
1203
1 atm ≡ 101325
≡ 1.01325
1.0332 — 760 14.695948
775
5142
1 Torr 133.322368
421
0.001333
224
0.001359
51
1
/
760
≈ 0.001315
789
— 0.019336
775
1 lbf/in2 6894
.757293
168
0.068947
573
0.070306
958
0.068045
964
51.714932
572
—See also
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References
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