Three things called queen, three different sizes
A queen comforter is about 88 by 96 inches. A queen quilt is about 90 by 95. A queen coverlet is about 84 by 88. And a queen mattress is 60 by 80, which is none of them. All three coverings are sold as queen, all three are correctly labelled, and all three are different objects cut to different charts. That is the entire reason people search separately for comforter dimensions and blanket dimensions and get different answers.
The word on the label tells you which chart the maker used, not how big the thing is. So the useful question is never what size is a queen comforter, it is how far does this particular covering hang past the mattress I own. That distance has a name, and it is the number this page is really about.
The formula
foot drop = covering length − mattress length
usable overhang = drop − mattress depth
Drop is how far the covering hangs past each side. Usable overhang is what is left after the thickness of the mattress has eaten into it, and it is the figure that decides whether the bed looks made or looks caught out. Around 4 inches of usable overhang is the point where a covering reads as deliberate. Mattress dimensions here are the same ones our bed size chart and rug size calculator use, so the three pages cannot disagree.
Worked example
Why standard bedding stopped fitting
The sizes on that chart were settled when a mattress was a mattress: seven to nine inches of springs, and the same bedding that covered it in 1970 would cover it in 1995. Then pillowtops arrived, then memory foam, then toppers on top of both, and beds quietly grew from nine inches deep to twelve, fourteen, sometimes sixteen. Bedding sizes did not follow, because they are set by convention rather than by any standards body, and convention moves slowly.
So the arithmetic that used to work stopped working. A fourteen inch drop over a nine inch mattress left five inches hanging, which looked right. The same fourteen inch drop over a fourteen inch mattress leaves nothing. This is why oversized and extra deep bedding exists as a category, and why the honest advice for anyone with a thick mattress is to buy the covering a size up from the bed: a king comforter on a queen bed is not a mistake, it is a common and sensible fix.
Comforter, duvet, quilt, coverlet
Worth separating, because the names get used interchangeably and they are not the same thing. A comforter is quilted with fill and is meant to be the whole top layer on its own. A duvet insert is the same object cut to the same chart, but designed to live inside a removable cover, which means the cover has to match the insert rather than the bed. A quilt is flatter and thinner, stitched through in layers, and typically runs longer and narrower than a comforter because it is often a layer rather than the answer.
A coverlet is the lightest and the shortest of the lot. It is cut to cover the top of the mattress and a little way down, usually over something else, and it is not trying to reach the bottom edge at all. If you buy a coverlet expecting comforter coverage you will be disappointed, and it will not be the coverlet's fault. Blankets, confusingly, are usually cut to the quilt chart, which is why most brands publish one set of numbers for both.
Every figure here is the middle of a range
There is no standards body for bedding. Twin, full, queen and king describe the mattress, and each brand decides for itself how much covering to hang past it. Differences of several inches on the same nominal size are completely routine, which is why one queen comforter drapes beautifully and the next one perches on top of the bed like a hat.
The practical consequence is simple. When a maker publishes actual dimensions, use those and ignore the word. When a maker publishes only the word, that tells you something about the maker. And if you are ordering online with a deep mattress, measure the drop you need before you buy rather than after, because a covering that is four inches short is four inches short forever.