Bed Sheet Sizes and Bedding Sizes, Deconstructed
Bed sheet sizes follow the mattress: Twin 38 by 75 inches, Twin XL 38 by 80, Full 54 by 75, Queen 60 by 80, King 76 by 80, California King 72 by 84. Fitted sheets are cut to those footprints. Everything else on the bed, from the flat sheet to the shams, follows convention rather than any standard.
That last sentence is the part the charts never mention, and it is why bedding bought by the label alone so often fits wrong. Four decisions sit underneath the numbers:
- How thick your mattress is, which decides the pocket depth you need
- Which King you own, standard or California
- How far you want the duvet or comforter to fall
- Which pillow sizes your cases and shams are actually cut for
The chart answers none of them.
What Size Are Bed Sheets for Each Mattress?
A fitted sheet matches the mattress footprint exactly: a Queen fitted sheet is cut 60 by 80 inches because that is what a Queen mattress measures. Flat sheets add tucking allowance on top and vary by maker, which is why their column below is a range. Sheet size and mattress size share one table:
| Size | Mattress | Fitted sheet cut | Flat sheet (typical range) |
|---|---|---|---|
| Twin | 38" × 75" | 38" × 75" | 66–75" × 96–104" |
| Twin XL | 38" × 80" | 38" × 80" | Usually shares the Twin flat |
| Full | 54" × 75" | 54" × 75" | 81–96" × 96–105" |
| Queen | 60" × 80" | 60" × 80" | 90–100" × 102–105" |
| King | 76" × 80" | 76" × 80" | 102–116" × 102–112" |
| California King | 72" × 84" | 72" × 84" | Usually shares the King flat |
Two honest footnotes. Some makers cut a Twin at 39 inches wide and a Full at 53, and manufactured mattresses commonly run a half inch to an inch under their nominal size once built. Neither matters for buying sheets; the label does.
The flat sheet column is a range for a reason.
Why Don't Sheet Sizes Match From Brand to Brand?
Because no standard exists. US mattress and bedding sizes are industry conventions, not regulations: the Consumer Product Safety Commission governs mattress flammability (16 CFR 1632 and 1633), the FTC governs fiber and origin labels, and neither says a word about dimensions. The one bed in America with a federally mandated size is the crib, where the mattress must measure at least 27.25 by 51.625 inches so a baby cannot slip between mattress and frame.
For adult beds, the mattress footprints have simply converged, which is why the fitted column above is dependable. Flat sheets never converged. A Queen flat runs 90 by 102 inches at one maker and 100 by 104 at another, and the difference is a design choice about how much fabric you get to tuck.
The conventions do produce three useful shortcuts. King and California King share one flat sheet cut at most makers, and only the fitted differs. Twin and Twin XL do the same, with the fitted running 5 inches longer for the XL. A Standard pillowcase fits both a Standard and a Queen pillow. None of the three is printed on the package, and only the fitted sheet ever tells the truth about fit.
What Size Comforter or Duvet Do You Need?
Wider than the mattress by twice the drop you want. A comforter needs to fall 8 to 12 inches past the mattress edge on each side, and for the sides to be covered completely, the drop has to be at least the depth of the mattress itself. The Sleep Foundation states it as a formula: needed width equals mattress width plus twice the mattress height.
The typical cuts, with the ranges honest:
| Size | Comforter (typical) |
|---|---|
| Twin | 66–68" × 86–88" |
| Full | 76–88" × 86–88" |
| Queen | 86–90" × 90–96" |
| King / Cal King | 102–110" × 86–98" |
The math explains two things the chart cannot. Oversized King comforters, cut around 110 to 120 inches wide, exist because a 15-inch hybrid mattress consumes most of a standard King comforter's drop and leaves the sides looking cropped. And many makers now sell a single King size meant to serve both King and California King, splitting the 4-inch difference in each direction.
For duvet covers, the working convention is a cover the same size as the insert or an inch or two smaller, so the insert fills the corners and the cover looks full rather than deflated. Some households prefer the looser look of a slightly larger cover. Both work; the snug fit is the tailored one. Coverlets follow their own rule, covering the top and sides but stopping deliberately short of the floor, and quilts often run a few inches longer than a comforter to allow a fold under the pillows.
How Thick Is Your Mattress?
This is the question every size chart skips, and it decides more fit problems than any other number. A fitted sheet's pocket must be at least as deep as the mattress, including any topper, or the corners will not stay seated. Standard pockets run about 7 to 12 inches; most mattresses today stand 10 to 12 inches; hybrids and pillow tops commonly reach 14 or 16. The margin has quietly disappeared, which is why sheets that fit beds for decades now pop loose.
Measure once, from the bottom edge of the mattress to the highest point of the sleeping surface, topper on. Our fitted sheets are cut with 18-inch pockets in Full through California King and 16-inch on Twin XL, on every line, and fit mattresses up to 20 inches thick. The full thickness-by-thickness verdict lives in our guide to Sheets for Thick Mattresses, and the pocket classes themselves are covered in our guide to Deep Pocket Sheets.
King or California King: Which Row Are You On?
The chart's favorite trap sits in its two bottom rows. A King is 4 inches wider; a California King is 4 inches longer and slightly smaller in total area. They are different beds with different fitted sheets: a King fitted sheet on a California King mattress runs 4 inches too wide and 4 inches too short, while the shared flat sheet usually survives the swap.
If you are not certain which bed you own, measure the width: 76 inches is a King, 72 is a California King. Choosing between them is its own decision, covered in our guide to King vs California King, and the sheet consequences are covered in our guide to King Sheets on a California King.
What Sizes Do Pillows, Pillowcases, and Shams Come In?
Five bed pillow sizes share one 20-inch width and differ only in length: Standard 20 by 26 inches, Super Standard 20 by 28, Queen 20 by 30, King 20 by 36. The Euro is the square exception at 26 by 26 and earns its keep propped against the headboard.
Pillowcases are named for the pillow they fit but sewn larger, a Standard case running roughly 20 by 30 to 32 inches so the pillow can actually get in. Shams are sized to the same inserts as cases; the difference is construction. A sham closes at the back and frames the pillow, often with a flat sewn border called a flange, typically about 2 inches wide. What a sham is for, and how the sizes layer front to back on a wide bed, are covered in our guide to What Is a Pillow Sham and our guide to King Bed Pillow Arrangement.
Bedding size FAQs
A few practical questions come up once the chart is in hand.
Do Full sheets fit a Queen bed?
No. A Full mattress is 54 by 75 inches and a Queen is 60 by 80, so a Full fitted sheet is 6 inches too narrow and 5 inches too short. Some makers cut one shared Full/Queen flat sheet, which drapes acceptably on either bed, but the fitted sheets are size-specific in both directions.
What size sheets does a Split King use?
A Split King is two Twin XL mattresses side by side, 76 by 80 inches in total. It takes two Twin XL fitted sheets, one per mattress, under a single King flat sheet and King comforter. Buying a King fitted sheet for a split base is the common mistake; the seam needs two.
What size is an Olympic Queen?
66 by 80 inches: 6 inches wider than a standard Queen, same length. It's a niche size, and bedding cut for it is genuinely scarce, so Queen sheets will not fit and King sheets run large. If you own one, buy bedding labeled for the size specifically.
What size mattress do two Twin beds make?
Two standard Twins side by side measure 76 by 75 inches: the width of a King, 5 inches shorter. King fitted sheets will not seat properly on the pair. Two Twin XLs are the combination that makes a true King footprint, which is exactly what a Split King is.
Do King pillowcases fit Standard pillows?
They slide on, but a King case is cut for a 20 by 36 inch pillow, so a Standard pillow leaves about 10 inches of empty fabric flapping at the open end. The reverse fails outright. Match the case length to the pillow and let the Standard case do double duty for Queen pillows instead.
The chart is the easy half of bedding sizes. Measure the mattress once, width and thickness both, and every row on it becomes a decision you have already made. Start with the bed you have, not the label you remember, and the rest is choosing the weave: our Percale and Sateen collections are cut to the numbers above, and the exact cut of every piece we sell, flat sheets to quilted shams, is listed on our size chart.
