"mentre" e "quando"
Both the two words "mentre" e "quando" have the meaning of "when....." , so is there any difference between "mentre" e "quando" when they mean " when .... " ?

Question

"mentre" e "quando"
Both the two words "mentre" e "quando" have the meaning of "when....."  ,  so is there any difference between "mentre" e "quando" when they mean " when .... "  ?

Answer

Sometimes /mentre/ can even be a translation for /as/, when it is related to coincidence in
time. A well known example (for Italians who like songsby Fabrizio De Andre`)

Original English (for instance, as is sung by Joan Baez, traditional ballad)
As I walked out over London bridge, one misty morning early ...

Italian well known version:
Mentre attraversavo London Bridge un giorno senza sole ...

Answer

mentre == when
only in cases where there are two (or more) events that share a common time.
This will be the context that could guide you.

Answer

I am curious  where you got the information about ' mentre == when ',
it is not correct.

mentre == while
quando == when