Vacuum Pressure – Units Converter

The table below can be used to convert between commonly used vacuum units:

% Vacuum	Torr (mm Mercury)	Micron	psia, (lb/in² abs)	Inches Mercury Absolute	Inches Mercury Gauge	kPa abs
0.0	760.0	760,000	14.7	29.92	0.00	101.4
1.3	750.0	750,000	14.5	29.5	0.42	99.9
1.9	735.6	735,600	14.2	28.9	1.02	97.7
7.9	700.0	700,000	13.5	27.6	2.32	93.5
21.0	600.0	600,000	11.6	23.6	6.32	79.9
34.0	500.0	500,000	9.7	19.7	10.22	66.7
47.0	400.0	400,000	7.7	15.7	14.22	53.2
50.0	380.0	380,000	7.3	15.0	14.92	50.8
61.0	300.0	300,000	5.8	11.8	18.12	40
74.0	200.0	200,000	3.9	7.85	22.07	26.6
87.0	100.0	100,000	1.93	3.94	25.98	13.3
88.0	90.0	90,000	1.74	3.54	26.38	12
89.5	80.0	80,000	1.55	3.15	26.77	10.7
90.8	70.0	70,000	1.35	2.76	27.16	9.3
92.1	60.0	60,000	1.16	2.36	27.56	8
93.0	51.7	51,700	1.00	2.03	27.89	6.9
93.5	50.0	50,000	0.97	1.97	27.95	6.7
94.8	40.0	40,000	0.77	1.57	28.35	5.3
96.1	30.0	30,000	0.58	1.18	28.74	4
96.6	25.4	25,400	0.49	1.00	28.92	3.4
97.4	20.0	20,000	0.39	0.785	29.14	2.7
98.7	10.0	10,000	0.193	0.394	29.53	1.3
99.0	7.6	7,600	0.147	0.299	29.62	1.0
99.87	1.0	1,000	0.01934	0.03937	29.88	0.13
99.90	0.75	750	0.0145	0.0295	29.89	0.1
99.99	0.10	100	0.00193	0.00394	29.916	0.013
99.999	0.01	10	0.000193	0.000394	29.9196	0.0013
100	0.00	0	0	0	29.92	0

Vacuum Units

The % of vacuum is a relative value where pressure at normal or standard atmosphere is the base value.

p_v% = 100% – (p_v / p_atm) 100% (1)

where

p_v% = vacuum (%)

p_v = absolute pressure (psia, kPa, bar ..)

p_atm = absolute presure at normal or standard conditions (psia, kPa, bar ..)

The vacuum with absolute pressure 4 kPa and standard pressure 101.4 kPa can be calculated as

p_v% = 100% – ((4 kPa) / (101.4 kPa)) 100%

= 96.1 %

The vacuum with absolute pressure 0.1 bar and standard pressure 1 bar can be calculated as

p_v% = 100% – ((0.1 bar) / (1 bar)) 100%

= 90 %