determining how many bytes a mysql row or table is consuming

Hi, I'm interested in determining the bytes consumed by rows or entire tables... we have a (large) table of application forms which users can SAVE to submit to us at a later date... the problem is cleaning out those which consume space and never come back to complete. So, i'd be wanting to find the diskspace consumed by certain rows (eg WHERE status='saved' or WHERE folder='trash'). Any ideas? Only thing I can think of is to jion all the fields together into one string and determin it's length, but i'm sure there's gotta be an easy way. Note: This doesn't have to be incredibly accurate either... if it was 80% acurate, this would be sufficient. TIA Justin French