A coffeemaker uses a basket or cone style filter. Below is a list of filter types for your specific coffeemaker cup size.

Basket Filters: (Paper or Permanent)
4 cup filter - 4 cup coffeemaker
8-12 cup filter - 8, 10 or 12 cup coffeemaker

Cone Filters: (Paper or Permanent)
# 2 cone filter - 4 cup coffeemaker
# 4 cone filter - 8, 10 or 12 cup coffeemaker