How is CPU Utilization calculated for Linux server?

How is CPU Utilization calculated for Linux server?

Telnet/SSH mode:

We are using /usr/bin/vmstat 1 3 command to get the CPU Utilization for Linux servers. 

Assume the output below: 

#/usr/bin/vmstat 1 3


procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
0  0      0 1810676 1359624 6483400    0    0    63    96  265  186 29 14 57  0  0
0  0      0 1810648 1359632 6483508    0    0     0    80 3056 8822  6  4 90  0  0
0  0      0 1808588 1359632 6485636    0    0     0     4 4690 12377 14  5 81  2  0

Formula:

CPU Utilization = 100-id ==> 100-81 ==> 19%

CPU Utilization = 19%