You measured the comforter. It came to 116 inches across. You went looking for a cover, and the largest size on the shelf was 104. There is nothing between them, and there is nothing above them.
This is the ordinary experience of owning an extra large bed in the United States. The mattress industry kept going after king — Cal king, oversized king, palatial king, Alaskan king — and the bedding industry mostly did not follow. Below is every oversized king duvet cover size in inches that people actually buy, what each one is usually for, the metric equivalent, and how to work out the number you need if yours is not on the list.
Why “oversized king” means five different things
There is no standard above king. “King” itself is loose — king duvet covers often start around 102 × 86 inches and run up to roughly 108 × 98. Past that, every mill and every brand picks its own numbers, so one company’s oversized king is 110 × 96 and another’s is 120 × 98. Ten inches apart, same name on the label.
Two things drive the difference. The first is mattress depth: a 16-inch pillow-top needs far more fabric falling down each side than a 9-inch mattress on the same frame. The second is how far you want the duvet to hang — a modest overhang and a full floor-length drape are different covers on an identical bed.
Which is why the size on the label is not the question worth asking. The question is what your own comforter measures.
Oversized king duvet cover sizes in inches
Width is always given first. Centimetres are rounded to the nearest whole number.
| Commonly called | Inches (W × L) | Centimetres | Usually bought for |
|---|---|---|---|
| Queen | 88 × 92 | 224 × 234 | A standard queen comforter |
| Oversized queen | 92 × 96 | 234 × 244 | Deeper queen mattress, longer drop |
| King | 102 × 86 | 259 × 218 | Where most king covers start |
| King, deeper drop | 104 × 90 | 264 × 229 | A king bed with a thick mattress |
| California king | 104 × 96 | 264 × 244 | The longer, narrower Cal king |
| Oversized king | 108 × 98 | 274 × 249 | The upper end of ready-made covers |
| Oversized king | 110 × 96 | 279 × 244 | The most commonly searched oversized size |
| Oversized king | 116 × 98 | 295 × 249 | Full floor-length drop on both sides |
| Palatial king | 120 × 98 | 305 × 249 | Very wide beds, hotel-style drape |
| Extra-long drop | 120 × 110 | 305 × 279 | High bed frames and platform bases |
| Alaskan king | 132 × 120 | 335 × 305 | The largest bed size sold — above what we can make (see the size limit below) |
If your measurement falls between two rows, it is not a problem to solve — every size in this table below the Alaskan king row, and every size between them, is made to order.
108 × 98 duvet cover
The largest size you will reliably find ready-made, and the usual answer for a California king with a deep mattress. If a retailer sells exactly one “oversized” option, this is normally it.
110 × 96 duvet cover
The size most people mean when they say oversized king. It gives a king mattress a generous overhang on both sides without pooling on the floor. It is also the size most often searched for and least often stocked.
116 × 98 duvet cover
Six inches wider again, which is roughly three extra inches of fabric hanging down each side. On a standard-height king this reaches close to the floor — the draped, made-bed look that photographs well and hides the base.
120 × 98 duvet cover (palatial king)
Ten feet across. Sold as palatial king by some brands and simply as extra-wide by others. This is the point at which ready-made supply effectively stops and made-to-measure becomes the only route.
Measure the comforter, not the bed
A made-to-measure cover is built around the duvet that goes inside it, so the mattress size tells you very little. Two king beds in the same room can take comforters eighteen inches apart in width. Measure the thing you already own:
- Lay it flat. Spread the comforter on the floor or across a made bed so no folds are pulling the edges inward.
- Measure side to side, seam to seam at the widest point. That is your width.
- Measure top to bottom, seam to seam from the head end to the foot end. That is your length.
- Round up to the nearest inch. Never round down — a cover a fraction roomier still hangs correctly, one a fraction short never does.
Then order those two numbers exactly as measured. Do not add inches of your own: on our custom duvet covers you enter the width and length of your duvet or comforter only, and the cover is made to that size. The one exception is a very thick, high-loft comforter — if yours is unusually deep, 2–3 inches extra on each measurement gives the loft somewhere to go. Our measuring guide walks through the same steps with diagrams.
The one size limit: 116 inches on one side
Cotton is woven on a fixed bolt width — ours is 305 cm — and once you allow for shrinkage in the wash and for hems and seams, the usable width comes down to 295 cm. That is a real constraint, not a marketing one, and it sets the only hard limit on what can be made: one of your two measurements has to be 116 inches (295 cm) or less. The other can be as long as you reasonably need.
In practice this rules very little out, because the limit applies to whichever side is shorter. A cover of 91 × 138 inches (230 × 350 cm) is fine — the short side sits well inside the limit. A cover of 118 × 118 inches (300 × 300 cm) is not, because neither side is under 295 cm. An Alaskan king at 132 × 120 inches (335 × 305 cm) falls the same way, which is why that one row in the chart above is beyond what we can make.
If the size you need appears in the ordering tool, enter your dimensions and order. If your duvet is larger than the options shown, or you are not certain which measurement to use, contact us before ordering and we will confirm what is possible.
The same sizes in centimetres
Buyers in the UK, Ireland, Europe and Australia work in centimetres, and the conversions are worth having in front of you because the round numbers do not line up. A 110 × 96 inch cover is 279 × 244 cm — nothing like the tidy 260 × 240 of a European super king set. If you are shopping a European size and your comforter is American, or the reverse, convert first and order the converted measurement rather than the nearest catalogue size.
One inch is 2.54 cm. Multiply, then round up.
Which fabric for a very large cover
Size changes how a fabric behaves. There is simply more of it, so weight and drape matter more than they do on a double bed.
- Cotton percale is crisp, cool and breathable, with a matte finish. It holds a made-bed shape well, which suits a large expanse of fabric.
- Cotton sateen is smoother and more lustrous, with a softer drape that falls closer to the bed. It reads more luxurious and shows the length of the drop.
Our cotton is woven and dyed in Italy, apart from Percale 200 TC, and the fabrics are Oeko-Tex Standard 100 certified — tested against strict criteria for harmful substances. Every cover closes with a zip rather than buttons, which matters more at this size: a ten-foot opening held by buttons gaps as you move. Covers can also be made reversible, so choosing two colours gives one oversized cover two looks. If you are undecided on the weave, our comparison of percale and sateen cotton goes into the difference in feel.
Don’t forget the sheets underneath
A bed large enough to need an oversized duvet cover almost always needs oversized sheets too, and a fitted sheet that pops off a deep mattress undoes the effect of everything above it. The same made-to-measure approach applies to oversized bed sheets, and we have written separately on why fit matters on a fitted sheet.
Frequently asked questions
What is the largest duvet cover size?
Among sizes sold under a name, the Alaskan king at roughly 132 × 120 inches (335 × 305 cm) is the largest. Made to measure, one side can be as long as you need, but the other has to be 116 inches (295 cm) or less, because that is the usable width of the cloth once shrinkage and hems are allowed for. An Alaskan king is above that on both sides, so it is beyond what we can make. Almost every other oversized size is not.
What size duvet cover for an oversized king comforter?
The same size as the comforter itself. Measure its width and length and order those numbers. Adding your own allowance is the most common ordering mistake and produces a cover that bunches. The exception is a very thick, high-loft comforter, where 2–3 inches extra on each measurement stops the cover pulling tight over the fill.
Is an oversized king duvet cover the same as a Cal king cover?
No. A California king is narrower and longer than a standard king, so a Cal king cover is typically around 104 × 96 inches. Oversized king describes extra width and extra drop, usually 108 × 98 and upward.
Will an oversized cover fit a standard king comforter?
It will go on, but it will not sit well. The extra fabric collects at the corners and the comforter slides inside the cover. If your comforter is a standard king, order a standard king size and get the drop you want by choosing a larger comforter, not a larger cover.
How do you put a cover on a bed this big?
Use the roll method. Turn the cover inside out and lay it on the bed, put the comforter on top corner to corner, roll the two together from the closed end to the open end, then reach inside, grab the corners and unroll. Zip and shake out. It is far easier than wrestling a cover this size overhead.
Order the size you actually measured
The reason oversized bedding is hard to buy is that retailers stock sizes, and your bed is a measurement. Made to order removes the gap: pick the fabric and the colour, type in the width and length you measured, and see the price immediately — there is no quote to request and no waiting to find out whether it can be done.
Order an oversized duvet cover in your exact size — your width, your length, in percale or cotton sateen.
