Comforter sizes can be quite confusing, since the comforters generally don't match up exactly (or even particularly well) to your mattress. Queen comforter sizes are particularly vexing, in part because some manufacturers view double (full) and queen comforters as interchangeable, while others do not.
It's unfortunately not unusual to purchase a comforter, only to find it's too small (most common) or too large (less common) for your particular mattress and needs.
This chart and guide will help you avoid this issue by explaining comforter size pitfalls and how to avoid them.
Comforter Sizes Vary Widely
As you can see from the chart below, mattress sizes are standardized, while comforter sizes are not:
|Bed||Mattress Measures **||Standard Comforter Widths|
|Standard Comforter Lengths|
|Crib||28" x 52"||28 - 36"||46 - 52"|
|Twin||39" x 75"||66 - 68"||86 - 88"|
|Double||60" x 80"||81 - 84" +||86 - 88"|
|Queen||60" x 80"||86 - 88"||96 - 100"|
|King (Standard/Eastern)||76-78" x 80"||102"||86 - 88"|
|California King||72" x 84"||107 - 110"||96 - 98"|
In fact, these sizes are only guidelines, and some manufacturers are currently either adding a few extra inches or shaving inches off of these "standard" sizes.
Be especially careful about very fluffy comforters, such as those filled with down. These tend to puff out the fabric so there is much less coverage than the dimensions listed on the package.
What Size Comforter to Buy?
If you have a twin-sized mattress, purchase a twin-sized comforter. Likewise, if you have a king-sized mattress, purchase a king-sized comforter. If you have a thick mattress, look for comforters at the top end of the dimensions listed in the chart above.
It gets trickier if you have a full-sized or queen-sized bed.
Full-sized mattresses can use either a full-sized (double-sized) or a queen-sized comforter, although if you purchase a wider queen comforter for a short bed, you may find its edges fall closer to the floor than you wish.
On the other hand, if you have a queen-sized bed and you purchase a comforter labeled for both full and queen use, it may not be wide enough to cover your bed adequately. In this case, you may want to shop specifically for the queen comforter size, or at least make sure the full/queen comforter you're considering is on the wider side (86" to 88", rather than 84").
Some of this may depend on the thickness of your mattress, as well. If you have a particularly thin bed—a futon or something like it—you probably can get away with a narrower comforter, since you'll need less of it on the sides of your bed. On the other hand, newer pillow-top mattresses can be as deep as 14" to 16", and you'll need a wider comforter to cover the sides of the mattress completely.
Mattress depths vary widely by manufacturer, although thicker mattresses are far more common than they were a few years ago. Standard and older mattresses average between 9" and 12" deep, which means they'll work with a standard comforter size.
Oversized Comforters Another Option
Some manufacturers are offering "oversized queen" and "oversized king" comforter sizes in addition to their standard sizes. These comforters have more width for their length: in the case of queen comforters, they're usually around 98" wide, and in the case of king comforters, they're usually around 115" wide. If you want a wide comforter but don't want to jump up to the next standard size, these may represent a good compromise.