Can someone explain to me how the reputation exploration is calculated?
If have compared the map exploration between me and a friend of mine. Even though I have explored about 5% more, they already have the 60% exploration reputation but I have not.

@AvidEric,
Please read it again, it does not say zoom in, it says zoom OUT.
"After the Ver. 1.1 update, you can check the progression of the exploration in each area by zooming out the world map."
As of today that still works, don't spread misinformation.

Also uncertain if any respawning chests will affect the completion percent. For example you have 100% then a chest respawns, will it give you 99%?

It seems as though there are added puzzles, spirits and chests when patch 1.1 rolled out. I have explored all the map in Teyvat before and I still come up as an average 90% completion rate on all regions in which includes finding new things when doing my dailies.