Note: This is post is not legal advice and is not intended to create an attorney-client relationship.
Question: What are the standard writer splits for a song?
Answer: The question presupposes that a song has more than one writer, a very common scenario. (For a more detailed discussion of why Creative Commons “audio” deeds do not work for (a) songs (separate from sound recordings) and (b) co-writes see “Carefully Co-Writing Without Creative Commons” and “Common Understanding: 10 Things Every Creator Should Know About Creative Commons Licensing” by ASCAP’s Joan McGivern).
There really aren’t any “standard” song splits, i.e., a standard division of the musical composition copyright between or among co-writers. The general rule of thumb is that if you have two writers, one of whom JUST rights music (or melody), and the other of whom JUST writes the lyric, then the copyright in the song should probably be divided 50/50.
Everyone has their own method for creativity, but in my experience it is not common for a songwriting team to divide up the duties that specifically. As long as you have an agreement as to who gets what share, it is less important what the “standard” is than what you agree. For example, some writing teams have an agreement that they’re going to split everything they write together 50/50 because it’s too much hassle to go through each song. They may write alone or with others, too, so those songs are separate from the team splits.
For group artists, dividing up songs can be one of the most contentious meetings the band will ever have. It’s a good idea to have some ground rules established for the band before you do any writing.
Also a good idea to have a split agreement with anyone you co-write with so that there are no questions about who owns what.