Is taking interest from banks haram or halal?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

All kinds of usury are forbidden in Islam, be they from a bank or from any other sources.

Allah Says (what means): {O you who have believed, fear Allah and give up what remains [due to you] of interest, if you should be believers.} [Quran 2:278]

Allah Says (what means): {But Allah has permitted trade and has forbidden interest.} [Quran 2:275]

Allah knows best.