How to calculate annual or promotional increment for Central Government employees as per 6th CPC..?

The logic is very simple, but everyone should know about the procedure of calculation.
We explain with some illustrations...

The increment is an increase in pay for each year in a particular date. As per 6th CPC the annual increment has been granted on 1st July of every year and the qualifying period for earning an increment is six months on 1st July. One increment is equal to 3% (three per cent)  of the sum of the pay in the pay band and the grade pay will be computed and rounded off to the next multiple of ten. 

"As per the Rule No.13 of CCS(Revised Pay) Rules 2008, “In the case of calculation of increments under the revised pay structure, paise should be ignored, but any amount of a rupee or more should be rounded off to next multiple of 10". 

To illustrate, if the amount of increment comes to Rs.1900.70 paise, then the amount will be rounded off to Rs.1900; if the amount of increment works out to be Rs.1901, then it will be rounded off to Rs.1910.”

And finally the increment amount will be added to the existing pay in the pay band.

For example :
An employee's pay in the pay band is Rs.10,230 and his grade pay Rs.2800, his basic pay = 10,230 + 2,800 = 13,030
His increment will be calculated as follows...
13,030 x 3% = 390.90
after rounded off to ten, it will be Rs.390 only.
Whereas, the another employee's pay in the pay band is Rs.10240 and his grade pay Rs.2800, his basic pay = 10,240 + 2,800 = 13,040
His increment will be calculated as follows...
13,040 x 3% = 391.20
then it will be rounded off to Rs.400.

Source: CGEN.in