A pillowcase is mainly a decorative, easy-to-change layer, while a pillow protector is a functional layer — usually zippered and often waterproof — that shields the pillow itself from moisture, dust, and everyday wear. They do different jobs, which is why many people use both at once rather than choosing one over the other.
What a Pillowcase Actually Does
A pillowcase is what you see and touch every night. It's chosen mostly for feel and appearance — the fabric against your skin, the color or pattern on your bed — and it's designed to be swapped out often, whether that's for laundry day or just to change up your bedding. Pillowcases are typically open on one end or closed with a simple envelope-style flap, which makes them quick to remove and wash.
What a pillowcase doesn't do especially well is protect the pillow underneath from moisture or fine particles, since most are made from a single layer of breathable fabric without a barrier built in.
What a Pillow Protector Actually Does
A pillow protector sits underneath the pillowcase, directly over the pillow itself, and its main job is to keep the pillow clean and dry over the long run. Protectors are usually zippered on all sides, so they fully enclose the pillow rather than just draping over it, and many — including ours — are waterproof, which matters most for anything that isn't easy to fully wash and dry on its own, like a buckwheat pillow.
Because a protector is meant to stay in place between washes of the pillowcase, it's built for durability rather than appearance. Most are made from a soft terry or microfiber face fabric with a waterproof backing, and a quiet, noiseless design so the barrier layer doesn't add its own rustle.
Pillowcase vs. Protector at a Glance
| Pillowcase | Pillow Protector | |
|---|---|---|
| Main purpose | Look and feel of your bedding | Shields the pillow from moisture and dust |
| Typical closure | Open end or envelope flap | Zippered, fully enclosed |
| Waterproof | No | Often, yes |
| How often it's washed | Weekly, with your sheets | Every few weeks, less often |
| Worn against skin | Yes, directly | No, worn under the pillowcase |
Do You Need Both
For most pillows, yes — they're complementary rather than redundant. The protector handles the parts a pillowcase can't: keeping moisture and daily buildup away from the pillow itself, especially useful for a filled pillow that isn't simple to launder in full. The pillowcase then handles everything you actually see and feel, and can be changed as often as you like without affecting what's underneath.
This is especially worth setting up for a buckwheat pillow, since the fill shouldn't be fully soaked in a washing machine. A protector keeps moisture away from the shell in the first place, which means less need to deep clean the pillow overall.
Choosing a Protector
Look for a few specific features rather than assuming all protectors are the same:
- Zippered on all sides so the pillow is fully enclosed, not just covered on top.
- A waterproof backing that still allows some airflow, rather than a fully sealed plastic layer that traps heat.
- A soft face fabric, like terry cotton, since you'll likely feel it through a thin pillowcase.
- A quiet design, so the protector itself doesn't add a crinkling sound under your pillowcase.
Our waterproof terry pillow protectors are built with all four of these in mind, and come in a pack of two so you can rotate one through the wash without leaving your pillow unprotected in the meantime.
What Happens Without a Protector
Skip the protector and a pillowcase ends up doing double duty it wasn't really built for. Over months of regular use, moisture from normal daily use can work its way through a single layer of pillowcase fabric and reach the pillow underneath, along with dust and general daily buildup that a pillowcase alone won't stop. For a filled pillow you can't easily machine wash in full, that buildup has nowhere to go, which is part of why a pillow can start to feel or smell different well before the fill itself is actually worn out.
None of this happens overnight, which is exactly why it's easy to skip a protector without noticing a problem right away — the effects show up gradually, over months rather than days.
Buying the Right Size
Protectors are sized the same way pillows are, so it's worth matching yours to the actual pillow dimensions rather than guessing. A protector that's too small will stretch tightly over the pillow and may not zip closed properly, while one that's too large can bunch up under the pillowcase and feel lumpy. If you have pillows in more than one size — a standard for the bed and a travel size for trips, for instance — plan on a protector for each size rather than trying to make one fit both.
Caring for Each
Pillowcases can go in with your regular sheet wash. Protectors tend to last longer with a gentler routine — a cool or warm wash rather than hot, and air drying or a low-heat tumble dry to protect the waterproof layer. Our care guide covers washing recommendations for every layer of your bedding, including the pillow itself.
If you're setting up a pillow for the first time, or replacing a worn-out cover, our covers and refills collection has both pillowcases and protectors sized to fit our pillows, and our sleep essentials collection covers the rest of what sits between you and your mattress.