Deep Pocket Mattress Cover: How to Get the Right Fit
A deep pocket mattress cover is a protector or pad with taller sides, made for mattresses around 15 inches thick or more, or for a regular mattress with a topper on it. To choose one, measure your mattress height (including any topper), add 2 to 3 inches so the elastic can tuck underneath, and buy a cover whose listed pocket depth meets or beats that number. Then pick the type based on what you need: spill protection, bed bug protection, extra cushioning, or a topper that stops sliding.
Most complaints about mattress covers come down to fit. A cover that is an inch too shallow pops off the corners every time you sit on the edge of the bed. One that is far too deep bunches up and leaves a ridge you can feel through the sheet.
Measure your bed before you shop
Mattress listings often round their height, and toppers add more than people expect. A 14-inch mattress with a 3-inch topper is a 17-inch stack, which is already past what a standard cover handles.
- Strip the bed down to the mattress and any topper you plan to keep.
- Stand a ruler or tape measure against the side, at a corner, and measure from the bottom seam to the highest point on top. On a pillow-top mattress, measure at the top of the pillow-top, not the main seam.
- Add 2 to 3 inches. That extra fabric is what wraps under the mattress and holds the cover in place.
- Check the mattress width and length too, if it's an older or non-standard size (some RV and antique beds are a few inches short of standard).
Write the number down. You'll need it again when you buy sheets.
What the depth labels usually mean
There's no industry standard for these terms, so treat them as rough guides and always look for the actual inch measurement on the listing.
- Standard pocket covers typically fit mattresses up to about 12 to 14 inches.
- Deep pocket covers usually fit roughly 15 to 18 inches.
- Extra deep or ultra deep covers aim at around 18 to 22 inches, sometimes more.
If a product only says "deep pocket" with no number, ask the seller or look in the size chart before ordering.
The main types of deep pocket mattress cover
"Mattress cover" gets used for several different products. Here's how they compare when depth is the main concern.
| Type | How it stays on | Best for | Trade-off |
|---|---|---|---|
| Fitted protector | Elastic around the edge or a stretchy side panel, like a fitted sheet | Spills, sweat, stains, everyday protection | Protects the top and sides only, not the underside |
| Strapped protector or pad | Elastic straps at each corner | Unusually tall or odd-sized mattresses | Can shift sideways more than a fully fitted cover |
| Zippered encasement | Zips closed around all six sides | Bed bugs, dust mite allergies | Needs a close depth match, and you have to lift the mattress to put it on |
| Quilted mattress pad | Usually fitted with elastic | Adding a thin layer of softness | Adds height, and many aren't waterproof |
Fitted protectors
This is what most people mean by a mattress cover. It goes on like a fitted sheet and comes off for washing in a couple of minutes. For tall mattresses, the depth of the side panel and the strength of the elastic decide whether it stays put. A fitted protector is the easiest type to live with if you wash it often (parents of small kids, pet owners, hot sleepers).
Strapped covers
Corner straps are a workaround for beds that don't match any size chart. Since the straps reach under the mattress rather than relying on fabric depth, they cope with a wider range of heights. But the top surface can drift, especially on smooth foam.
Encasements
A zippered encasement is the right call if bed bugs or dust mite allergies are the main worry, because it seals the whole mattress. The depth has to match closely. Too shallow and the zipper won't close; too deep and the loose fabric wrinkles. Expect a two-person job to fit one on a heavy hybrid.
Quilted pads
Pads add a soft layer, which some people want on a firm mattress. Remember that the pad itself adds height, so your sheets need even deeper pockets afterward.
What to check beyond depth
- Elastic quality. Thin elastic loosens after repeated washing, and a deep cover puts more strain on it because there's more fabric to hold.
- The top fabric. This is the part you lie on through your sheet, so it affects temperature. Breathable fabrics like bamboo blends tend to sleep cooler than plain polyester.
- A waterproof layer that stays quiet. Older vinyl-backed protectors crinkle when you move. Look for listings that say the lining is quiet or silent.
- Washing instructions. Some waterproof layers can't handle high dryer heat. Check before you buy if you plan to wash weekly.
- What the top surface protects against. Waterproofing stops liquids. Stain repellent and antimicrobial finishes are separate features, so read the listing for each one.
Using a cover over a mattress topper
A lot of people search for a deep pocket mattress cover because they've added a topper and their old protector no longer fits. A fitted cover over both layers does two jobs: it protects the topper (which is often harder to clean than the mattress) and it holds the topper from sliding around.
The usual layer order is mattress, then topper, then protector, then fitted sheet. Measure the full stack. If you haven't picked a topper yet, you can browse thicknesses in our mattress topper collection and plan the cover depth around it.
Where the Dosaze protector fits, and where it doesn't
The Dosaze Cooling Bamboo Waterproof Mattress Protector is a fitted protector that stays in place with a high-quality elastic band. The top is a patented bamboo-blended, silver-infused fabric, and it has a 100% waterproof lining that blocks liquids. It's described as quiet, with no white noise, which matters if a crinkly protector has kept you awake before.
It also protects against allergens, bed bugs, dust mites and stains, has a stain repellent finish, and uses Glacier-pro bamboo fabric meant to keep you cool and sweat-free. The anti-microbial silver is described as gentle on all skin types.
Where it may not suit you:
- It's a fitted protector, not a zippered encasement. If you need the whole mattress sealed on all six sides, an encasement is the better tool.
- It doesn't add cushioning. If your mattress feels too firm, pair it with a topper instead of expecting the protector to soften things.
- Before ordering for a very tall mattress or a thick topper stack, compare your measurement with the size details on the product page. If anything is unclear, our FAQ page covers the 60-night sleep trial, shipping and returns.
You can see the protector alongside our sheets, comforters and pillowcases in the Dosaze bedding collection.
Your sheets need the same depth
A deep cover fixes nothing if the fitted sheet on top is still too shallow. Every layer you add (topper, pad, protector) pushes the height up a little more, so take your final measurement with the cover on and shop for sheets against that number. When you browse sheets, look for the stated pocket depth on each listing rather than assuming "deep" means deep enough.
Frequently asked questions
How deep is a deep pocket mattress cover?
Most covers sold as deep pocket fit mattresses roughly 15 to 18 inches tall, while extra deep versions aim at around 18 to 22 inches. There's no fixed standard, so check the inch measurement on the listing. Measure your mattress plus any topper and add 2 to 3 inches for tuck.
Will a deep pocket cover fit a regular mattress?
It will go on, but if it's much deeper than your mattress the extra fabric can bunch and leave ridges under your sheet. A cover with strong elastic handles a small mismatch better than a loose one. Aim for a cover within a few inches of your actual height.
Can I put a mattress cover over a mattress topper?
Yes, and it's a common reason people need a deep pocket cover. The usual order is mattress, topper, protector, then fitted sheet. Measure the combined height of the mattress and topper before buying.
Do I need deep pocket sheets if I use a deep pocket mattress cover?
Usually yes. The cover adds a little height of its own, and if you also have a topper, a standard fitted sheet may not reach around the corners. Measure with the cover on and buy sheets with a listed pocket depth that covers it.
Are waterproof mattress covers noisy?
Some are, especially older styles with a vinyl or plastic backing that crinkles when you move. Many newer protectors use quieter waterproof linings. Look for a listing that says the cover is quiet or silent, as the Dosaze Cooling Bamboo Waterproof Mattress Protector does.
