Is Pakistan's Independence Day August 14 Or August 15?

Sixty-five years ago Pakistan got freedom and we celebrate our independence day on August 14 while India who also got freedom with us celebrates it on August 15. This question arises every year when both the countries got freedom on the same day why there is a difference of one day between the independence day.
Our elders tell us that Pakistan was established on Ramazan ul Mubarak 27 and the the last Friday of Ramazan (Juma ul Wida). Then we are told that Pakistan came into being on August 14 and Pakistan is one day older to India. When we have a look at the calender of the year 1947, it shows that there was Thursday on August 14 and the 28th of Ramazan not 27th. When we look at the first postal stamps of Pakistan that were issued after 11 months of the freedom of Pakistan, therre is clearly printed the August 14, 1947, as the day of independence of Pakistan. One concludes that the Independence day of Pakistan is 15 th not the 14 th of August. Then why the first birth day of Pakistan was celebrated on August 14, one gets confused.