Although the dimensions of comforters can vary from one comforter maker to another, the standard sizes for most comforters on the market are:

Twin Size Comforter: from 68 X 86 to 70 X 90

Full size comforter:  from 78 X 86 to 80 X 90

Queen size comforter:  from 86 X 86 to 92 X 96

King size comforter:  from 86 X 92 to 110 X 96

Other sizes:  Although mattresses are available in extra-long twin size and California king size, makers of comforters don't have special sizes for them.  Use a regular twin size or a regular king size to fit your special-sized mattress.

Our Comforters 

Our twin-size comforters measure 60 X 90 and our queen/full size comforters measure 90 x 108.