Has the episode count for Black Clover been announced? According to Wikipedia it's 13 eps, MAL hasn't said anything and some say it's 50/51 eps.

Does anyone really know how many episodes the series is going to be? 

Considering the slow pacing, I think it's going to be longer than 12/13 episodes... but I may be wrong.
Nothing "official" has been announced yet, it was assumed that it's going to have 13 episodes because that's kind of the norm nowadays and Funimation did list it at one point as having that many episodes, but they were wrong about episode order before so, who knows.

Recently though, Yonkou_Prod, a fan-site that was responsible for several anime leaks in the past, claimed that the anime's episode order has been expanded to 51 episodes, and as unlikely as that sounds, they seem confident about their claims...

Whether and who you want to believe is totally up to you, but the fact of the matter is: we don't know anything official yet.