Kanthas are traditionally worked by village women on old cloth, mainly soft, discarded dhotis and saris. Layers of old white dhotis used by men or white or faded coloured saris are held together in running stitches along the edges, using thread drawn out of the faded borders of the discarded saris. These borders are generally torn off and preserved carefully for the purpose by kantha makers. The number of layers of cloth used depends on the use for which the kanthas is meant. If it is to be a quilt for use in the mild winters of Bengal, five or six layers of soft, fine cloth are used. Three or four layers usually suffice for other purposes. The top and bottom layers of a kantha are always white or of a very light colour, so that embroidery with faded threads drawn from the sari borders is not lost. The muted colours lend a charming, soft, pastel effect to the completed kantha.

Kanthas meant for use as quilts are called lepkanthas, and those designed as counterpanes are called sujanikanthas. Kanthas also serve as covers for boxes and mirrors, as pillowcases. Stoles for women and shawls for men; they are very popular as diapers for babies too.

The main characteristic of a kantha is the patterned running stitches in white thread with which the kantha-maker covers the whole surface of the piece. The stitches secure the layers together and the surface gets a delicate, rippled look.