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Standard atmospheric pressure is 101,325 pascals = 1,013.25 hPa = 101.325 kPa
Important to know: 1 Pa = 1 N/m2 ≡ 94 dBSPL and 1 bar = 105 Pa
1 kPa = 103 Pa = 1000 Pa = 1000 N/m2 ≡ 154 dBSPL
Conversion of sound units: pascals to dBSPL
Pressure = force / area p = F / A
Please enter two values, the third value will be calculated.
Conversions of many more pressure units
Pressure units conversion chart
Sorted from low to high
| Pressure or mechanical stress unit, p | Symbol | Definition | Relation to SI unit pascal, Pa = N/m² |
| pascal (metric SI unit) | Pa | ≡ N/m² | = kg/(m·s²) |
| barye (cgs unit) | - | ≡ 1 dyn/cm² | = 0.1 Pa |
| poundal per square foot | pdl/sq ft | ≡ 1 pdl / ft² | ≈ 1.488 164 Pa |
| millimetre of water (3.98 °C) | mmH2O | ≈ 999.972 kg/m³ × 1 mm × g | = 9.806 38 Pa (= 0.999972 kgf/m²) |
| pound per square foot | psf | ≡ 1 lbf / ft² | ≈ 47.880 259 Pa |
| centimetre of water (3.98 °C) | cmH2O | ≈ 999.972 kg/m³ × 1 cm × g | = 98.0638 Pa |
| torr | torr | ≡ 101 325 / 760 Pa | ≈ 133.322 368 4 Pa |
| millimetre of mercury | mmHg | ≡ 13595.1 kg/m³ × 1 mm × g ≈ 1 torr | = 133.322 387 415 Pa |
| inch of water (3.98 °C) | inH2O | ≈ 999.972 kg/m³ × 1 in × g | = 249.082 Pa |
| pièze (mts unit) | pz | ≡ 1000 kg / m·s² | = 1 kPa |
| centimetre of mercury | cmHg | ≡ 13 595.1 kg / m³ × 1 cm × g | = 1.333 223 874 15 kPa |
| foot of water (3.98 °C) | ftH2O | ≈ 999.972 kg / m³ × 1 ft × g | = 2.988 98 kPa |
| inch of mercury | inHg | ≡ 13 595.1 kg / m³ × 1 in × g | = 3.386 388 640 341 kPa |
| pound per square inch | psi | ≡ 1 lbf / 1 in² | ≈ 6.894 757 kPa |
| foot of mercury | ftHg | ≡ 13 595.1 kg/m³ × 1 ft × g | = 40.636 663 684 091 9 kPa |
| short ton per square foot | - | ≡ 1 sh tn × g / 1 ft² | ≈ 95.760 518 kPa |
| atmosphere (technical) | atm | ≡ 1 kgf / cm² | = 98.0665 kPa |
| bar | bar | - | ≡105 Pa = 100 000 Pa |
| atmosphere (standard) | atm | - | ≡101 325 Pa |
| kip per square inch | ksi | ≡ 1 kipf / in² | ≈ 6.894757 MPa |
| kilogram-force per square millimetre | kgf/mm² | ≡ 1 kgf / mm² | = 9.806 65 MPa |
| Unit | Equivalent energy measures |
| Pounds 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 (GPa) |
The prefix "giga" means "1,000,000,000", so one gigapascal = 1,000 MPa = 1,000,000 kPa = 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. |
Conversion chart
Pressure, temperature and standard height (altitude or elevation)
Values in "standard atmosphere"
Elevation Temperature Air 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
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
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Air pressure depends on temperature and indirectly on altitude
| Pascal (Pa) is the metric 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. |
| 1 Pa = | 1 N/m2 |
| 10 µbar | |
| 10 dynes/cm2 |
| 1 µbar = | 0.1 N/m2 |
| 0.1 Pa | |
| 1 dynes/cm2 |
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