King Size Bed Sheet Dimensions: Fitted, Flat, and Pillowcase Sizes

What Size Is a King Bed Sheet?

A king bed sheet is sized to a king mattress, which measures 76 inches wide by 80 inches long. Sounds simple, right?

Well, only the fitted sheet matches that footprint exactly, so don't leave the page just yet. The flat sheet and pillowcases carry their own numbers, and in king's case both of them are larger than you might expect.

Here's the whole set, in inches and centimeters; this way we cover it for everyone. 

Centimeter figures are converted from inches and rounded to the nearest whole number, and you'll find that other brands do it this way as well, so keep this in mind as you're shopping. 

King Fitted Sheet Measurements

The king fitted sheet is cut to 76 inches by 80 inches across the top panel. Line it up against a queen and the length is identical; the entire difference between the two sizes is 16 inches of width. That's a useful thing to know, because it explains why people assume the two are closer than they are.

What the number doesn't describe is the sides. King sheets measure the top of the mattress and stay silent on how far the sheet travels down, which is the part that determines whether it holds.

Therefore, two sheets can both read 76" x 80" and behave like completely different products once they're on a bed. So, make sure you keep this in mind. 

What Are the Dimensions of King Size Bed Sheets?

King size bed sheets measure 76" x 80" fitted, 110" x 102" flat, and 20" x 40" for the pillowcases. Most sets include two pillowcases at that size, though it's worth reading the listing rather than assuming.

You'll occasionally see a king fitted sheet listed at 78" x 80" instead. That's a manufacturing tolerance rather than a different bed; the mattress underneath is still 76 inches wide. Both are describing the same size.

King Flat Sheet Size

A king flat sheet measures 110 inches wide by 102 inches long. Put that next to a 76" x 80" mattress and the flat sheet is 34 inches wider and 22 inches longer than the bed. It's the largest single piece of fabric in the standard sheet lineup, and it's a notable difference. 

That size gap is the reason king flat sheets get searched more than almost any other measurement in this category.

People see the number, hold it against their bed, and assume something went wrong at the factory, and that it's time to hit that panic button. 

Why a King Flat Sheet Is So Much Wider

A flat sheet has to cover your body, hang over both sides of the bed, and leave enough length at the foot to tuck under the mattress. On a king, it also has to do that for two people who are each pulling their own direction. Cut it to the size of the mattress and none of that happens, so that's where it's all coming from. 

The extra width gives you roughly 17 inches of drape per side once the sheet is centered. That sounds generous until you're sharing the bed; on a king, the flat sheet is the piece most likely to end up entirely on one person. It's also why the drape disappears fast on a deeper mattress, since every inch of height eats into the same surplus.

What Size Is a King Flat Sheet?

The king flat sheet is 110" x 102", which converts to roughly 279 x 259 cm. It has no elastic, no corners, and no depth to accommodate; it's a rectangle, and the two numbers on the package are the only ones that matter.

Because there's nothing fitted about it, the flat sheet is the one piece where sizing up is a legitimate move rather than a mistake. Some people running a deep mattress buy the flat sheet a size up and keep the fitted sheet in king. Nothing about that is wrong, so it's more of a preference thing for most shoppers. 

King Pillowcases Are a Different Size

Here's the detail that trips up more king buyers than any measurement on the bed itself. King pillowcases are 20" x 40". Every other size in the lineup, from twin through California king, ships queen or standard cases at 20" x 30".

Ten inches of length doesn't sound like much until the pillow is in your hands and the case won't close over it. Here's how the two compare.

The mismatch goes wrong in both directions, though, so it's worth checking for queen and king beds.

A king pillow in a 20" x 30" case leaves the end exposed and puts the seams under constant strain. On the other hand, a standard pillow in a 20" x 40" case leaves a flap of empty fabric hanging off the end of the bed, which looks exactly as unfinished as it sounds. If you're not sure which pillows you actually own, our pillow size guide sorts that out.

Why Two King Sheets Can Fit Differently

Two king fitted sheets can carry identical 76" x 80" labels and perform nothing alike. The variable is depth, and it's the one measurement the package barley talks about. 

And the bad news is that king mattresses make this worse than any other size, and it's simple physics. Seventy-six inches of fabric span means more sheet, more weight, and more leverage pulling against whatever is holding the corners.

Add a topper or a mattress protector and the profile grows while the grip stays the same, so this is something worth noting as well. 

How Mattress Depth Changes Fit

A fitted sheet has to reach the underside of the mattress and stay there. When the mattress runs deeper than the sheet was cut for, the fabric runs out before it clears the bottom edge, and what's left is holding on by an inch of corner.

On a twin, that marginal grip might survive the night. On a king, there's twice as much sheet pulling on it every time someone rolls over. That's why the same construction that works fine in a guest room fails on the primary bed; the failure isn't random, it's proportional to the size of the sheet.

What a Powerband Does Differently

Most fitted sheets gather a strip of elastic into the four corners. On a king, that means four small points are holding 76 inches of width in place, and the fabric between them has nothing supporting it at all. The elastic fatigues, the grip loosens, and the corner lets go. And then poof, say goodbye to your bed sheets. 

Our sheets use a Powerband instead. It's a stretch band engineered to hold tension around the perimeter rather than concentrating the work at the corners, so the grip is distributed across the whole edge and accommodates a range of mattress depths rather than one fixed profile.

On the widest sheet in the lineup, that difference is the most noticeable. Plus, if you have comfortable clothes for exercise, you'll find that our Powerband looks similar, and that's on purpose. 

King vs. Queen and California King Sheets

King gets compared in two directions, and both comparisons surprise people. Queen is the same length; California king is actually narrower. Here's how the three fitted sheets line up.

Look at the California king row for a moment. It's the only size in the lineup that's longer than a king while being narrower, which is why people assume it's the bigger bed. It isn't; it's a different shape, built for height rather than width.

Will King Sheets Fit a California King?

No. A king fitted sheet is 76" x 80" and a California king mattress is 72" x 84", so the sheet is 4 inches too wide and 4 inches too short. The length is what kills it; there's simply no fabric to reach the corners at the foot of the bed.

It's the most common question in the king category and it runs in both directions, so we gave it proper room in our California king sheet dimensions guide.

How to Choose King Sheets for Your Bed

King is usually a shared bed, which changes the decision. You're solving for two sets of preferences and a sheet large enough that every weakness in its construction shows up.

Thread count, material, and measurements play the biggest roles, and we cover them in detail below.

Start With Fit, Not Thread Count

Thread count is the number printed largest on the package and the one that tells you least. It counts threads per square inch, which says nothing about breathability, durability, or whether the sheet stays on your mattress. The industry figured out long ago that a bigger number moves product.

On a king, fit is even more decisive than it is elsewhere. A loose sheet on a twin gathers slightly at one corner; a loose sheet on a king creates a ridge of fabric right down the middle of the bed, between two people, all night. If you want the real story behind the number, we took it apart in our piece on thread count myths.

Match the Material to How You Both Sleep

A king almost always holds two people with two different thermostats. One of you is throwing off the covers at 2am and the other is pulling them back. The sheet can't split the difference by being average; it has to move heat well enough that the hot sleeper stops overheating without leaving the other one cold.

That's the case for performance fabric over luxury feel. Ver-Tex® sheets are cool to the touch on contact, which helps the sleeper who runs hot without changing much for the one who doesn't.

 Dri-Tec promotes airflow and moves moisture instead of trapping it. If your household's temperature swings by season, Hyper-Wool and Hyper-Linen handle the range better than a fixed-feel fabric will.

Measure Your Mattress Depth Before You Buy

Run a tape measure down the side of your mattress and write down the total height. Include the pillow top. Include the topper and the protector, because the fitted sheet has to wrap all of it rather than just the mattress.

This is the single number that prevents the most common king sheet failure. It's also why a Powerband matters more here than anywhere else: a band that holds tension across a range of depths means 76 inches of sheet isn't relying on four fatiguing corners.

If you're still sorting out the bed itself, don't panic, because our king mattress dimensions guide has the full footprint for you. 

How to Fold a King Size Fitted Sheet

Nobody asks this about a twin. King is the size where folding becomes a genuine problem, and it's worth solving rather than shoving the sheet in the closet in a ball.

The good news is that the difficulty isn't your technique. It's geometry, and once you know what's actually going wrong the fix is straightforward.

Why a King Fitted Sheet Is Harder to Fold

A king fitted sheet is 76 inches wide. That's wider than most people's wingspan, which means the standard approach of holding the sheet out in front of you and squaring it up in the air is physically impossible. You run out of arms before you run out of sheet.

Every other size lets you cheat. A twin at 39 inches or a full at 54 inches will hang more or less flat between two hands. A king won't; the middle sags, the corners drift, and the elastic edge curls in on itself while you're still trying to find the second corner.

The answer isn't better technique in the air. It's to stop working in the air.

Folding a King Fitted Sheet Step by Step

Folding stinks. We get that, but what if we had a little secret folding method for you?

Nest the corners first, then let a flat surface do the rest. A bed works better than a table here, since you need the room.

1. Turn the sheet inside out and slide one hand into each of the two top corners.
2. Bring your hands together and fold the right corner over the left, so one pocket nests inside the other.
3. Reach down and collect the two bottom corners the same way, then nest all four pockets together.
4. Lay the bundle on a bed or table and straighten the elastic edge into a rough rectangle.
5. Fold the curved elastic edge inward, then fold the rectangle in thirds and again in half.

The flat surface is what makes this work at king scale; there's simply too much fabric to manage while holding it.

One more thing worth noting: a sheet with a well-built band holds its shape through the fold, while a sheet with tired corner elastic fights you the entire way and never sits square in the closet.

Finding Your King Size Bed Sheet Dimensions

King size bed sheet dimensions come down to three numbers: 76" x 80" fitted, 110" x 102" flat, and 20" x 40" pillowcases. They're tied to the mattress rather than the brand, so they hold no matter whose sheets you're buying. The pillowcase is the one to write down, since king is the only size that breaks from the 20" x 30" standard.

The number worth measuring yourself is depth. Add up the mattress, the topper, and the protector, then choose a sheet built to stretch across that range instead of one cut to a single profile.

On the widest bed in the house, size gets you close and fit is what keeps it from falling apart throughout the night.