Mattress and Sheet Sizes Explained

The sizes, in inches

US mattress sizing is standardised, so the label is reliable. It is worth knowing the actual dimensions, because the names are not intuitive.

• Twin: 38 by 75 inches. Children, bunk beds, small guest rooms.
• Twin XL: 38 by 80 inches. Same width, five inches longer. Standard in college dorms and useful for tall single sleepers.
• Full, also called Double: 54 by 75 inches. Roomy for one, tight for two.
• Queen: 60 by 80 inches. The most common size sold and the default for two adults.
• King: 76 by 80 inches. Sixteen inches wider than a queen, the same length.
• California King: 72 by 84 inches. Four inches narrower than a king and four inches longer. Not interchangeable with king sheets.

Pocket depth is the part that catches people out

A fitted sheet has to stretch over the mattress and tuck underneath. Mattresses have got deeper over the last two decades, and pillow-tops and toppers add more. A sheet that fits the length and width perfectly will still pop off in the night if the pocket is too shallow.

Measure from the top surface of the mattress to the bottom edge, including any topper you use. Standard-pocket sheets suit mattresses up to about 14 inches. Deep-pocket handles 15 to 17. Beyond that you need extra-deep, which is a smaller market and worth checking before you commit to a mattress.

How many sets to own

Two sets per bed is the minimum that lets you strip and remake immediately while the other set is washed. Three is comfortable, and means a set can be out of rotation without any pressure. More than three per bed mostly buys storage problems.

For a guest bed, two sets is plenty. For a child's bed, three is worth it for the obvious reason.

Duvets and comforters run on a different scale

Duvet covers are sized to the duvet insert, not the mattress, and inserts are generally cut wider than the bed so the cover drapes over the sides. A queen duvet is typically 88 by 88 inches against a 60 by 80 mattress.

If you like a lot of overhang, or if two people pull the covers, sizing the duvet up one step from the mattress is a common and sensible move. A king duvet on a queen bed is a deliberate choice, not an error.

Thread count matters less than the weave

Above roughly 400, thread count stops correlating with how a sheet feels and starts being a marketing number, sometimes inflated by counting plies. Weave and fibre do more work. Percale is crisp and cool. Sateen is smooth and warmer. Linen is heavier, breathes best, and softens over years rather than washes.

Pick the weave for how you sleep, then buy the best fibre you can at that weave, and ignore the number on the packaging.