The “inch of mercury” (inHg) is a unit of pressure commonly used in aviation, meteorology, and refrigeration. It originates from the barometric pressure measurement practice using a column of mercury. This unit became a staple due to its early adoption in weather forecasting and its accurate and consistent measurements. An interesting fact is that an inch of mercury is approximately equal to 33.86 millibars or 3386 Pascals, but what truly distinguishes it is its historical significance in the development of modern atmospheric science.
In the 17th century, Evangelista Torricelli, a student of Galileo, first discovered that atmospheric pressure could sustain a column of mercury, laying the groundwork for this unit. His invention, the barometer, revolutionized how we understand and predict weather, marking the inch of mercury as more than just a unit—it’s a nod to the evolution of scientific inquiry and practice.
The kilopascal (kPa) is a metric unit of pressure that often finds its application in various everyday and scientific contexts, such as meteorology, engineering, and automotive industries. One intriguing aspect of the kilopascal is its relationship to atmospheric pressure. At sea level, the standard atmospheric pressure is 101.3 kPa. This means when the weather forecast mentions a high or low-pressure system, it’s essentially describing variations in kilopascals, subtly influencing everything from weather patterns to flight dynamics.
In the world of construction and engineering, knowing a material’s tolerance in kilopascals is crucial for ensuring structural integrity and safety. For instance, the force exerted by an average car tire on the ground is about 220 kPa, showcasing kilopascals as a pivotal unit in designing components that need to withstand specific pressures. Such applications highlight its crucial role in both routine and critical decision-making processes.
Inches of mercury | Kilopascals |
---|---|
0
inHg
|
0
kPa
|
1
inHg
|
3.38639
kPa
|
2
inHg
|
6.77278
kPa
|
3
inHg
|
10.15917
kPa
|
4
inHg
|
13.54556
kPa
|
5
inHg
|
16.93194
kPa
|
6
inHg
|
20.31833
kPa
|
7
inHg
|
23.70472
kPa
|
8
inHg
|
27.09111
kPa
|
9
inHg
|
30.4775
kPa
|
10
inHg
|
33.86389
kPa
|
11
inHg
|
37.25028
kPa
|
12
inHg
|
40.63667
kPa
|
13
inHg
|
44.02306
kPa
|
14
inHg
|
47.40945
kPa
|
15
inHg
|
50.79583
kPa
|
16
inHg
|
54.18222
kPa
|
17
inHg
|
57.56861
kPa
|
18
inHg
|
60.955
kPa
|
19
inHg
|
64.34139
kPa
|
20
inHg
|
67.72778
kPa
|
21
inHg
|
71.11417
kPa
|
22
inHg
|
74.50056
kPa
|
23
inHg
|
77.88695
kPa
|
24
inHg
|
81.27333
kPa
|
25
inHg
|
84.65972
kPa
|
26
inHg
|
88.04611
kPa
|
27
inHg
|
91.4325
kPa
|
28
inHg
|
94.81889
kPa
|
29
inHg
|
98.20528
kPa
|
30
inHg
|
101.59167
kPa
|
31
inHg
|
104.97806
kPa
|
32
inHg
|
108.36445
kPa
|
33
inHg
|
111.75084
kPa
|
34
inHg
|
115.13722
kPa
|
35
inHg
|
118.52361
kPa
|
36
inHg
|
121.91
kPa
|
37
inHg
|
125.29639
kPa
|
38
inHg
|
128.68278
kPa
|
39
inHg
|
132.06917
kPa
|
40
inHg
|
135.45556
kPa
|
41
inHg
|
138.84195
kPa
|
42
inHg
|
142.22834
kPa
|
43
inHg
|
145.61472
kPa
|
44
inHg
|
149.00111
kPa
|
45
inHg
|
152.3875
kPa
|
46
inHg
|
155.77389
kPa
|
47
inHg
|
159.16028
kPa
|
48
inHg
|
162.54667
kPa
|
49
inHg
|
165.93306
kPa
|
50
inHg
|
169.31945
kPa
|
51
inHg
|
172.70584
kPa
|
52
inHg
|
176.09223
kPa
|
53
inHg
|
179.47861
kPa
|
54
inHg
|
182.865
kPa
|
55
inHg
|
186.25139
kPa
|
56
inHg
|
189.63778
kPa
|
57
inHg
|
193.02417
kPa
|
58
inHg
|
196.41056
kPa
|
59
inHg
|
199.79695
kPa
|
60
inHg
|
203.18334
kPa
|
61
inHg
|
206.56973
kPa
|
62
inHg
|
209.95612
kPa
|
63
inHg
|
213.3425
kPa
|
64
inHg
|
216.72889
kPa
|
65
inHg
|
220.11528
kPa
|
66
inHg
|
223.50167
kPa
|
67
inHg
|
226.88806
kPa
|
68
inHg
|
230.27445
kPa
|
69
inHg
|
233.66084
kPa
|
70
inHg
|
237.04723
kPa
|
71
inHg
|
240.43362
kPa
|
72
inHg
|
243.82
kPa
|
73
inHg
|
247.20639
kPa
|
74
inHg
|
250.59278
kPa
|
75
inHg
|
253.97917
kPa
|
76
inHg
|
257.36556
kPa
|
77
inHg
|
260.75195
kPa
|
78
inHg
|
264.13834
kPa
|
79
inHg
|
267.52473
kPa
|
80
inHg
|
270.91112
kPa
|
81
inHg
|
274.29751
kPa
|
82
inHg
|
277.68389
kPa
|
83
inHg
|
281.07028
kPa
|
84
inHg
|
284.45667
kPa
|
85
inHg
|
287.84306
kPa
|
86
inHg
|
291.22945
kPa
|
87
inHg
|
294.61584
kPa
|
88
inHg
|
298.00223
kPa
|
89
inHg
|
301.38862
kPa
|
90
inHg
|
304.77501
kPa
|
91
inHg
|
308.16139
kPa
|
92
inHg
|
311.54778
kPa
|
93
inHg
|
314.93417
kPa
|
94
inHg
|
318.32056
kPa
|
95
inHg
|
321.70695
kPa
|
96
inHg
|
325.09334
kPa
|
97
inHg
|
328.47973
kPa
|
98
inHg
|
331.86612
kPa
|
99
inHg
|
335.25251
kPa
|
100
inHg
|
338.6389
kPa
|
If you like the website, share it on social media.