Deep Pocket Fitted Sheets: How to Fit Mattresses 16 to 22 Inches Deep
3 November 2026
If your fitted sheet snaps off a corner every night, your mattress is probably deeper than the sheet was made for. Pillow-tops, hybrid mattresses and toppers have pushed many beds past 16 inches (41 cm). Most store-bought fitted sheets still stop there.
This guide shows you how to measure your bed properly, which pocket depth to buy, and what to do when no standard sheet is deep enough.
Why fitted sheets slip off deep mattresses
A fitted sheet stays on because its corners wrap under the mattress. If the pocket is too shallow, the elastic sits on the side of the mattress instead of underneath it. Every time you roll over, the tension pulls a corner loose.
Three things usually cause it:
- Thicker mattresses. Pillow-top and hybrid mattresses commonly run 14 to 18 inches deep, and some luxury models go past 20.
- Toppers. A 2 to 4 inch topper adds straight to the depth your sheet has to cover, and many people forget to count it.
- Shrinkage. Cotton can shrink up to about 5% in the first washes. A sheet that only just fits when new can come up short later.
The fix isn't a stretchier sheet or sheet straps. It's a pocket deep enough to tuck well under the mattress.
How to measure your mattress depth
It takes two minutes with a tape measure. Measure with everything that will sit under the sheet already on the bed.
- Put your topper and mattress protector on the mattress, the way you sleep on it.
- Measure from the bottom edge of the mattress straight up to the highest point of the top, at the side, not the corner.
- Measure at two or three points and use the deepest reading. Pillow-tops are often deeper in the middle.
- Write the depth down in inches or centimetres, along with the mattress width and length.
No tape measure to hand? The RocketLinen custom studio can estimate your mattress size from a photo taken on your phone. Check the estimate with a tape before you order.
What pocket depth to buy
Labels usually say "fits mattresses up to X inches". Pick a sheet whose X is at least your measured depth, mattress and topper together. If you're right on the limit, size up: cotton can shrink a little in the first washes.
| Mattress + topper depth | What to buy | RocketLinen option |
|---|---|---|
| Up to 12 in (30 cm) | Standard fitted sheet | Standard size |
| 13–16 in (33–41 cm) | Deep pocket, "up to 16 in" or more | Standard size |
| 17–18 in (43–46 cm) | Extra-deep pocket | Made to measure |
| 19–22 in (48–56 cm) | Extra-deep pocket, rarely in stores | Made to measure |
| Over 22 in (56 cm) | Almost never sold off the shelf | Made to measure |
RocketLinen's standard fitted sheets fit mattresses up to 16 inches (41 cm) deep. For anything deeper, sheets are made to your exact measurement.
What to look for in a deep pocket fitted sheet
- Elastic all the way round. Corner-only elastic lets the long sides lift. Full-perimeter elastic grips the whole base of the mattress.
- The pocket depth on the label, not "deep". "Deep pocket" means different things at different brands. Look for an actual number in inches or centimetres.
- Pure cotton. Cotton breathes and stays cooler than microfiber, which matters on a thick mattress that already holds heat. It also lasts years longer.
- Head and foot markers. On a rectangular bed, a label marking the head or foot end saves a frustrating second attempt.
- The right width and length too. Bed sizes with the same name differ between countries: a UK king, a US king and a UAE king are all different sizes. Check all three measurements, not just the depth.
Custom fitted sheets made to any depth
When no standard sheet is deep enough, a made-to-measure one is the only fix that lasts. RocketLinen makes fitted sheets to any depth, in pure long-staple cotton, cut to your exact width, length and depth.
It works for more than deep mattresses: split kings, adjustable bases, antique and oversized beds, and sizes that sit between standard ones.
How it works:
- Open the RocketLinen custom studio.
- Choose fitted sheet, then your thread count and colour.
- Enter your width, length and depth in inches or centimetres.
- You see your price, delivery cost and delivery time before you pay.
Timing. Each custom order is made for you, which takes 12 to 14 days. International delivery to the US, UK, Canada and elsewhere then takes 5 to 7 days, so allow about three weeks in total.
Frequently asked questions
How deep is a deep pocket fitted sheet?
There's no fixed standard. Most "deep pocket" sheets fit mattresses 15 to 16 inches (38 to 41 cm) deep, and "extra-deep" sheets fit 18 to 22 inches (46 to 56 cm). Always check the number on the label.
Do I include my mattress topper when measuring?
Yes. The sheet has to cover the mattress and the topper together, so measure with the topper in place.
My fitted sheet keeps popping off. Is it too small?
Usually the pocket is too shallow, not the sheet too narrow. Measure your mattress depth with the topper on and compare it with the depth on the label.
Can I get a fitted sheet deeper than 22 inches?
Yes, but rarely in stores. RocketLinen makes fitted sheets to any depth, in any width and length.
How long does a custom fitted sheet take to arrive?
About three weeks outside the UAE: 12 to 14 days to make it, then 5 to 7 days for international delivery.
Will a cotton sheet shrink off my deep mattress?
Cotton can shrink up to about 5% in its first washes. RocketLinen cuts every sheet with that shrinkage allowed for, so it still fits after washing.
