Whenever you people are in need of authentic information then search your required data in the official website of any country or organization. I searched about borders length in official webs of Pakistan but all in vain, I found it in CIA Factbook which is also an authentic authority:
Land boundaries of Pakistan:
total: 6,774 km
border countries: Afghanistan 2,430 km, China 523 km, India 2,912 km, Iran 909 km
https://www.cia.gov/library/publicat...k/geos/pk.html