Vacuum Pressure Units Conversion Table

Several of the questions I receive each week by email deal with scientific calculations or conversion of various units. One popular request relates to the conversion of micrograms, ppm and percent. Several years ago to address this question, I posted a table of weight to ppm units ("Conversion Factors microgram, nanogram, ppm, ppb and percent") which has proven to be very popular.

Because of the large number of vacuum pumps attached to HPLC and MS systems, another common conversion question relates to vacuum units. Due to the different applications and regions of the world, the desired unit often varies. It is for this reason that I develop unit conversion tables as I find these tables provide for a convenient way to print out and/or keep handy in a binder for future reference. Widespread computer use coupled to freely available page reader software (e.g. Adobe PDF) provides another means to store useful information as a pdf file too. I present this "Vacuum Pressure Units Conversion Table" in a viewable and an optionally available downloadable form [click HERE to download].

VACUUM PRESSURE UNITS CONVERSION TABLE:

*Some of the more commonly used values are shown in boldface type. ** Absolute Vacuum..

% Vacuum	Torr (mm Mercury)	kPa abs	Inches of Mercury	Micron	PSI
0.0	760.0	101.4	0.00	760,000	14.7
1.3	750.0	99.9	0.42	750,000	14.5
1.9	735.6	97.7	1.02	735,600	14.2
7.9	700.0	93.5	2.32	700,000	13.5
21.0	600.0	79.9	6.32	600,000	11.6
34.0	500.0	66.7	10.22	500,000	9.7
47.0	400.0	53.2	14.22	400,000	7.7
50.0	380.0	50.8	14.92	380,000	7.3
61.0	300.0	40	18.12	300,000	5.8
74.0	200.0	26.6	22.07	200,000	3.9
87.0	100.0	13.3	25.98	100,000	1.93
88.0	90.0	12	26.38	90,000	1.74
89.5	80.0	10.7	26.77	80,000	1.55
90.8	70.0	9.3	27.16	70,000	1.35
92.1	60.0	8	27.56	60,000	1.16
93.0	51.7	6.9	27.89	51,700	1.00
93.5	50.0	6.7	27.95	50,000	0.97
94.8	40.0	5.3	28.35	40,000	0.77
96.1	30.0	4	28.74	30,000	0.58
96.6	25.4	3.4	28.92	25,400	0.49
97.4	20.0	2.7	29.14	20,000	0.39
98.7	10.0	1.3	29.53	10,000	0.193
99.0	7.6	1.0	29.62	7,600	0.147
99.87	1.0	0.13	29.88	1,000	0.01934
99.90	0.75	0.1	29.89	750	0.0145
99.99	0.10	0.013	29.916	100	0.00193
99.999	0.01	0.0013	29.9196	10	0.000193
100	0.00	0	29.92	0	0