Pressure units conversion chart Sorted from low to high

Pressure or mechanical stress unit, p Symbol Definition

Relation to SI unit pascal, Pa = N/m

pascal (SI unit) Pa N/m = kg/(ms)barye(cgs unit) - 1 dyn/cm = 0.1 Papoundal per square foot pdl/sq ft 1 pdl / ft 1.488 164 Pa

millimetre of water (3.98 C) mmH2O 999.972 kg/m 1 mm g= 9.806 38 Pa (= 0.999972 kgf/m)

pound per square foot psf 1 lbf / ft 47.880 259 Pacentimetre of water (3.98 C) cmH2O 999.972 kg/m 1 cm g = 98.0638 Patorr torr 101 325 / 760 Pa 133.322 368 4 Pa

millimetre of mercury mmHg 13595.1 kg/m 1 mm g 1 torr = 133.322 387 415 Pa

inch of water (3.98 C) inH2O 999.972 kg/m 1 in g = 249.082 Papize (mts unit) pz 1000 kg / ms = 1 kPacentimetre of mercury cmHg 13 595.1 kg / m 1 cm g = 1.333 223 874 15 kPafoot of water (3.98 C) ftH2O 999.972 kg / m 1 ft g = 2.988 98 kPainch of mercury inHg 13 595.1 kg / m 1 in g = 3.386 388 640 341 kPapound per square inch psi 1 lbf / 1 in 6.894 757 kPafoot of mercury ftHg 13 595.1 kg/m 1 ft g = 40.636 663 684 091 9 kPashort ton per square foot - 1 sh tn g / 1 ft 95.760 518 kPaatmosphere (technical) atm 1 kgf / cm = 98.0665 kPabar bar - 105 Pa = 100 000 Paatmosphere (standard) atm - 101 325 Pakip per square inch ksi 1 kipf / in 6.894757 MPakilogram-force per square millimetre kgf/mm 1 kgf / mm = 9.806 65 MPa

Unit Equivalent energy measuresPounds per square inch

(psi, PSI, lb/in2, lb/sq in)

Commonly used in the U.S., but not elsewhere. Normal atmospheric pressure is 14.7 psi, which means that a column of air one square inch in area rising from the Earth's surface up to space weighs 14.7 pounds.

Atmosphere (atm) Normal atmospheric pressure is defined as 1 atmosphere. 1 atm = 14.6956 psi = 760 torr.

Torr (torr)

Based on the original Torricelli barometer design, one atmosphere of pressure will force the column of mercury (Hg) in a mercury barometer to a height of 760 millimeters. A pressure that causes the Hg column to rise 1 millimeter is called a torr (you may still see the term 1 mm Hg used; this has been replaced by the torr). 1 atm = 760 torr = 14.7 psi.

Bar (bar)

The bar is nearly identical to the atmosphere unit. One bar = 750.062 torr = 0.9869 atm = 100,000 Pa.

Millibar (mb or mbar)

There are 1,000 millibar in one bar. This unit is used by meteorologists who find it easier to refer to atmospheric pressures without using decimals. One millibar = 0.001 bar = 0.750 torr = 100 Pa.

Pascal (Pa)

1 pascal = a force of 1 Newton per square meter. 1 Newton is the force required to accelerate 1 kilogram one meter per second per second = 1 kg m/s2; this is actually quite logical for physicists and engineers. 1 pascal = 10 dyne/cm 2 = 0.01 mbar. 1 atm = 101,325 Pascals = 760 mm Hg = 760 torr = 14.7 psi.

Kilopascal (kPa)

The prefix "kilo" means "1,000", so one kilopascal = 1,000 Pa. Therefore, 101.325 kPa = 1 atm = 760 torr and 100 kPa = 1 bar = 750 torr.

Megapascal (MPa)

The prefix "mega" means "1,000,000", so one megapascal = 1,000 kPa = 1,000,000 Pa. Such high pressures are rarely encounterd.

Gigapascal The prefix "giga" means "1,000,000,000", so one gigapascal = 1,000 MPa = 1,000,000 kPa

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Pressure conversion chart Values in a standard atmosphere

Elevation Temperature Pressure (feet) (degrees C) (millibar = hPa)

0 15.0 1013.25

500 14.0 995 1,000 13.0 977 1,500 12.0 959 2,000 11.0 942 2,500 10.0 925 3,000 9.1 908 3,500 8.1 891 4,000 7.1 875 4,500 6.1 859 5,000 5.1 843 5,500 4.1 827 6,000 3.1 812 6,500 2.1 797 7,000 1.1 782 7,500 0.1 767 8,000 -0.9 752 8,500 -1.8 738 9,000 -2.8 724 9,500 -3.8 710

10,000 -4.8 697 10,500 -5.8 683 11,000 -6.8 670 11,500 -7.8 657 12,000 -8.8 644 12,500 -9.8 632 13,000 -10.8 619 13,500 -11.8 607 14,000 -12.7 595 14,500 -13.7 583 15,000 -14.7 572 15,500 -15.7 560 16,000 -16.7 549 16,500 -17.7 538 17,000 -18.7 527 17,500 -19.7 516 18,000 -20.7 506 18,500 -21.7 495 19,000 -22.7 485 19,500 -23.6 475 20,000 -24.6 465 20,500 -25.6 456 21,000 -26.6 446 21,500 -27.6 437 22,000 -28.6 428 22,500 -29.6 419 23,000 -30.6 410 23,500 -31.6 401 24,000 -32.6 392 24,500 -33.6 384 25,000 -34.5 376 25,500 -35.5 368

(GPa) = 1,000,000,000 Pa = 9,870 atm = 10,000 bar. Pressures of several gigapascals can convert graphite to diamond or make hydrogen a metallic conductor.

Page 2 of 3Pressure units conversions - conversion unit pressure convert pascals psi Pa - sengpiel...

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26,000 -36.5 360 26,500 -37.5 352 27,000 -38.5 344 27,500 -39.5 336 28,000 -40.5 329 28,500 -41.5 322 29,000 -42.5 315 29,500 -43.5 307 30,000 -44.5 301 30,500 -45.4 294 31,000 -46.4 287 31,500 -47.4 281 32,000 -48.4 274 32,500 -49.4 268 33,000 -50.4 262 33,500 -51.4 256 34,000 -52.4 250 34,500 -53.4 244 35,000 -54.4 238 35,500 -55.4 232 36,000 -56.3 225 36,500 -57.3 219 37,000 -58.3 213 37,500 -59.3 207 38,000 -60.3 200 38,500 -61.3 194 39,000 -62.3 188 39,500 -63.3 182 40,000 -64.3 176

Pascal (Pa) is the SI unit of pressure and the standard pressure unit in the MKS metric system, equal to one newton

per square meter or one "kilogram per meter per second per second." Sounds impressive, but in traditional English

terms a pascal is only 0.000 145 pounds per square inch (0.020 885 lbf/ft2 or 0.007 50 mmHg). Thus pressure is more

commonly measured in kilopascals (kPa), with 1 kPa = 0.145 lbf/in2. Air pressure is also measured in hectopascals (hPa),

with 1 hPa = 1 millibar. The unit is named after Blaise Pascal (1623 - 1662), French philosopher and mathematician,

who was the first person to use a barometer to measure differences in altitude.

Page 3 of 3Pressure units conversions - conversion unit pressure convert pascals psi Pa - sengpiel...

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