The official website for the Black Clover anime revealed that it will end with episode 170, which will air on March 30th.
Furthermore, episode 170 will contain an important announcement for the franchise.
Black Clover premiered in Japan in October 2017. The anime was originally listed with 51 episodes, but continued into a new season with episode 52 being released in October 2018, and continued again into a new season in October 2019.
It's worth remembering that the anime already went on hiatus, which began on April 28, 2020 due to the effects of the COVID-19 , and resumed with episode 133 on July 7.
Source: ANN