A comforter (American English) is a type of blanket. Comforters are intended to keep the user warm, especially during sleep. Comforters are generally large and rectangular in shape, filled with natural or synthetic insulative material and encased in a shell/covering. Like quilts, comforters are generally used with a set of bed sheets. Duvets are a form of comforter, traditionally filled with feathers though often made of synthetic fibres.
Comforter sizes correspond with bed sizes: twin, full, queen, king, and cal-king. Comforter sizes run slightly larger than actual bed sizes to allow for draping over the sides of the bed. Typical sizes in the United States for comforters are:
- Twin = 64" (162.56 cm) Width x 87" (220.98 cm) Length
- Queen / Full = 87" (220.98 cm) Width x 87" (220.98 cm) Length
- King = 101" (256.54 cm) Width x 90" (228.6 cm) Length.
A comforter is sometimes covered for protection and prolonged use. Comforter covers are similar in principle to pillowcases, usually closed with zippers or buttons.
Sometimes a comforter is sold as a "bed in a bag". This term usually denotes an entire set of bedding, including either a comforter or duvet with its cover.
Filling - Comforters are filled with layers of material such as polyester batting, down feathers, wool, or silk. Comforters can also be made out of fur, usually with a backing of satin or silk. The loft of the filling determines the weight as well as the level of insulation. The comforter is stitched or quilted to secure the filling and keep it evenly distributed.
Shell/Covering - The outer shells of comforters are typically constructed using cotton, silk, or polyester fabrics or blends, of varying thread counts. Comforter shells vary in design and color, often designed to coordinate with other bedding.
See also 
- "Bedding Sets - Finding What's Right for You" Home-Furniture-Guide.com. June 2007.