Standard length is 16 inches, 3 rows of 16 inch = 4 feet. 4 ft x 4 ft x 8 ft = 1 cord, it works out for measure purpose, and fits in most all wood stoves. Split, can be anywhere from rounds to half's, quarters, down to 4 inch wedges.
I cut a lot of wood, Douglas Fir, Larch, it does not need much time to season, but it doesn't hurt either. I split all different sizes for different months/temp's, some as large as 8"x12", some small as 4"x4". I heat my home and garage/shop with wood only. Wood stove in the house will put out 90k btu's, but it never needs to.