There is no fixed criteria to rank armed forces of the world, therefore there is no fixed rank for any one country except for America that is ranked highest in all rankings. I have a rating supposedly from CIA and MI6(Declassified) that puts Pakistan at 6th. According to that rating:
1) America
2) China
3) Russia
4) India
5) Israel(I believe this spot should have been given to Pakistan)
6) Pakistan
7) South Korea
8) U.K
9) Germany
10) France
Mind you, these ratings(military/Intelligence based) are much more dependable than civilian sources since they take some very important factors into account such as WMDs, Experience, Performance in Battlefields, Morale, Discipline among other things.
The source that puts Pakistan at 15th puts France and Italy higher than us which I consider an insult since in the last war they fought(WWII), France didn't even put up resistance and Italy's most successful campaign was when they bombed Ethiopian tribesmen clad in loin cloths, wielding spears and wooden shields from the air with mustard gas, cowardly !