Detailed DA calculation for July 2013

Year	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Last 12 month Average
2012	198	199	201	205	206	208	212	214	215	217	218	219
2013	221	223	224	226	228	231							220.66

6th Pay commission New Pay scale Date: Jan 2006

The index as per Dec 2005 is 115.77

12 month average from July 2012 to June 2013 220.66 (see table).

Rise in index after New Pay scale is fixed = 220.66-115.77 =104.8

This means that you have to spend Rs 104.89 "more" to buy an item which you have bought with Rs 115.77 in Jan 2006.

In other words you need to spend (104.89/115.77) x 100 = Rs 90.6 "more" that you might have bought with Rs 100 in Jan 2006.

That means, you will need to spend Rs 190.6 for the same item which you bought with Rs 100 with your new pay scale in Jan 2006.

That is why you are likely to get 90% as Dearness Allowance of your basic effective July 2013.