A:The compulsory length of a beard is a fist-length all round.
When the beard exceeds this length then the person is allowed to trim the excess and bring it to a fist-length.
Tell yourself that Rasulullah Sallallaahu Alayhi wa Sallam kept a beard and instructed others to do the same.
He is allowed to trim on the cheeks, neck and throat and to cut the excess after a fist-length. So although the beard may be of the required length, it can still be kept neat.
Moulana Yusuf Laher