[AX,H]=SUBPLOTSCM(NROWS,NCOLS,FIGWIDTH,FIGHEIGHT,W,E,NS,EW,N,S) where:
NROWS is the number of rows of subplots, NCOLS the number of columns.
FIGWIDTH and FIGHEIGHT are in centimeters. Defaults: 44, 25.5.
W, E, N, and S are the margin widths (in cm) for the west, east, north,
and south sides of the figure. Defaults: 1.4, 0.3, 0.2, 1
NS and EW are the margin widths between subplots. Defaults: 0.05, 0.05.
AX is a handle to the axes created.
H is the figure handle.

If FIGWIDTH or FIGHEIGHT are strings, SUBPLOTSCM will use the string
value as the subplot width or height and calculate the figure height or
width. E.g. if a subplot height of 3 cm is desired, FIGHEIGHT='3'

The functionality overlaps with some other file exchange submissions, but I like my version, and thought others might too.