Meaning of “fifty-fifty” - Learner’s Dictionary

fifty-fifty

adjective, adverb uk us /ˌfɪftiˈfɪfti/ informal

shared equally between two people:

Let's divide the bill fifty-fifty.
a fifty-fifty chance

If something has a fifty-fifty chance, it is equally likely to happen or not to happen:

We have a fifty-fifty chance of winning the game.

(Definition of “fifty-fifty” from the Cambridge Learner’s Dictionary © Cambridge University Press)