You splurged on the giant bed, it arrived, and now you're staring at a mattress that no store-bought sheet will cover. That's the catch nobody warns you about: the beds are easy to buy, but oversized King sheets are the hard part. Standard King bedding stops at 76 x 80 inches, and an Alaskan King is a foot and a half wider than that in every direction. Here's how to figure out exactly what your bed needs and where to actually get it.
What counts as an oversized King?
"Oversized King" is a family of sizes, not one bed. They all start bigger than a standard King and go up from there. Getting the right oversized King sheets means knowing which one you actually own, because a few inches here decides whether a fitted sheet grips the corners or slides off.
| Size | Dimensions | Best for |
|---|---|---|
| Standard King (reference) | 76" x 80" | Two adults, no extras |
| Wyoming King | 84" x 84" | A little more room, tightest bedroom fit |
| Alberta King (Vermont King) | 96" x 96" | Two adults plus a couple of kids or pets |
| Texas King | 80" x 98" | Tall sleepers who want length over width |
| Alaskan King | 108" x 108" | The whole family, the largest standard size |
SGI also cuts sheets for the in-between and combined sizes some makers use, including Short Alaskan King, Family King, and Family XL. Those measurements vary a bit from one mattress brand to the next, so check the size chart on the product page against your own mattress before ordering rather than assuming they all match. If you're only a step up from standard and cross-shopping, our California King sheets guide and King size bed sheets guide cover the standard end of the range.
Why a standard King sheet won't stretch to fit
People try it, so it's worth saying plainly. A King fitted sheet is built for a 76 x 80 inch mattress. Put it on a Wyoming King and you're already 8 inches short on width and 4 on length. On an Alaskan King you're 32 inches short each way, which is nearly three feet of bed with nothing over it. The corners won't reach, the elastic strains, and the sheet peels off the moment you move.
Flat sheets fail the same way, just less visibly: what looks tucked at bedtime has pulled loose by 2 a.m. The fix isn't a deeper pocket or a stronger elastic. It's a sheet cut to the actual size, which is the entire reason oversized King sheets exist as their own category.
Cotton or bamboo for a big bed?
Both work at any size, so the choice comes down to how you sleep. A big bed usually means more bodies on it, which means more warmth, so this matters more here than on a standard King.
- ✓Bamboo viscose. Cooling and moisture-wicking, which is what you want when two adults plus kids or a dog share the bed. It's the pick for hot sleepers and warmer rooms.
- ✓Egyptian cotton. The crisp, structured, hotel-bed feel that softens with every wash. A safe year-round choice if you run neutral rather than hot.
SGI's bamboo oversized sheet set comes in every oversized size named above, from Wyoming King through Alaskan King. If you'd rather have cotton, or your bed is an odd measurement that isn't on any standard chart, the custom-size 600 thread count cotton set is cut to numbers you supply, so nothing is off-limits.
100% Bamboo Viscose Oversized Sheet Set
- Cut for Wyoming, Texas, Alberta, Short Alaskan, Family, and Alaskan King
- Cooling bamboo viscose for shared beds
- White, Light Grey, Dark Grey, Sea Glass
From $114.99
Shop the setThe two things people forget to size up
Once the sheets fit, two more pieces still need to match the bed, and both are easy to overlook until they turn up too small.
The first is protection. A mattress this large is a serious investment, and a standard protector leaves the outer foot of it exposed. SGI's oversized mattress protector is waterproof and cut to the same oversized sizes, so the whole surface is actually covered.
The second is the duvet. A King duvet cover floats on top of a big bed instead of draping over the sides. SGI's 1000 thread count pinch pleat duvet cover runs up to Oversized King and Super Oversized King so it hangs the way it should. You can see the full range on the oversized bedding collection page.
Keeping oversized sheets in good shape
Big sheets take up a lot of a washer, so don't cram them in with a full load or they won't come clean. Wash cool or warm, skip the fabric softener (it coats the fibers and dulls both bamboo and cotton over time), and tumble dry low. Pull them out slightly damp and put them straight on the bed if you can, which saves you ironing a sheet the size of a small tent. Buy a second set if the bed gets daily use, since laundering something this size takes long enough that going a night without a spare is a real hassle.
A few common questions
Will King sheets fit an Alaskan King bed?
No. A King sheet is made for 76 x 80 inches and an Alaskan King is 108 x 108, so the sheet falls about 32 inches short on each side. You need sheets cut specifically for the Alaskan King size.
What size sheets does a Wyoming King take?
Wyoming King sheets are cut for an 84 x 84 inch mattress. SGI lists Wyoming King as its own size, so you order it by name rather than sizing up from a King set.
My mattress isn't on any standard chart. Now what?
Some oversized and combined beds are built to measurements that don't match a named size. Measure your mattress (width, length, and depth) and order the custom-size set cut to those exact numbers.
Are bamboo or cotton sheets better for a shared family bed?
Bamboo, for most people. More bodies on the bed means more heat, and bamboo viscose wicks moisture and sleeps cooler. Choose cotton if you prefer a crisp, structured feel and don't run hot.
SHEETS THAT ACTUALLY FIT YOUR BED
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