up to now vs til now

up to now and til now both are adverbs.

Word	Noun	Adjective	Verb	Adverb
up to now	No	No	No	Yes
til now	No	No	No	Yes

As adverbs, up to now and til now are synonyms defined as:

up to now and til now: used in negative statement to describe a situation that has existed up to this point or up to the present time

Other synonyms of up to now include as yet, heretofore, hitherto, so far, thus far, until now, yet.

up to now (adverb)	til now (adverb)
used in negative statement to describe a situation that has existed up to this point or up to the present time	used in negative statement to describe a situation that has existed up to this point or up to the present time
prior to the present time