A good pillowcase size guide starts with your pillow, not your bed. Measure the pillow seam to seam, then pick the matching label: standard cases are made for 20 by 26 inch pillows, queen cases for 20 by 30 and king cases for 20 by 36. After that, the closure and the fabric decide whether the fit feels tidy or baggy.
That last part is where most people get caught out. Two cases with the same "standard" label can differ by several inches, and a case that fits on day one can feel different after a hot wash. This pillowcase size guide covers what we check when fitting cases onto pillows: how much extra fabric is normal, how to measure the case itself, which closures run snug, and what washing does to cotton.
If you still need to work out which pillow you own, our guide to standard, queen and king pillow sizes walks through that first. Here we stay focused on the case.
Pillowcase size guide: the quick chart
The chart below pairs each label with the pillow it is designed for. The case sizes in the third column come from a Utah State University Extension sewing guide for a classic open end pillowcase, so they show how much extra room a traditional case is cut with.
| Case label | Pillow it is made for | Open end case, finished size | What to watch for |
|---|---|---|---|
| Standard | 20 by 26 inches | About 20.5 by 30 inches | Some brands sell a 20 by 30 inch case as "standard", which leaves a loose tail on a true standard pillow |
| Queen | 20 by 30 inches | About 20.5 by 34 inches | Often sold as "standard/queen", so check the listed length |
| King | 20 by 36 inches | About 20.5 by 40 inches | Fits a smaller pillow too, but you will fold the spare length under |
| Euro | 26 by 26 inches | Usually sold as a square sham | Does not swap with rectangular cases |
| Body | No single size | Buy by exact length | Measure the pillow before ordering |
Read any pillowcase size guide chart, ours included, as a starting point. Labels are names, not measurements.
Every maker cuts a little differently. The listed length in inches is what actually tells you how the case will sit.
Why does a pillowcase measure bigger than the pillow?
A pillow has to slide in, and an open end case has to cover it without the filling poking out of the hem. So the case is cut longer. In the extension guide above, the open end case for a 20 by 26 inch pillow finishes at about 30 inches long, roughly 4 inches past the pillow, and only half an inch wider.
Width gets very little extra because the pillow's thickness eats into it. A full, puffy pillow pulls the sides of the case inward as it lofts up. A flat pillow leaves the same case looking slightly roomy along the sides.
Length is where the slack goes. That spare tail is what folds over the end of the pillow, and it is also what annoys people.
A common complaint from shoppers is that the cases bundled with sheet sets look like a sail on a normal pillow, even though the label says standard.
Usually the case is fine. It is just cut for a queen and labeled for both.
How do you measure a pillowcase for the right fit?
Most pillowcase size guides tell you to measure the pillow. That matters, but the case needs its own check, because the number on the packet does not always describe the usable space inside. Here is the routine we use:
- Turn the case inside out and lay it flat on a bed or table. Smooth it without stretching the fabric.
- Run a soft tape along the seam for the length, then across the closed end for the width.
- Note where the usable space stops. On an open end case that is the hem. On an envelope case it is the fold of the inner flap. On a zippered cover it is the zipper's end stop.
- Compare those numbers with your pillow measured seam to seam, not over the curve.
Then do the real test. Put the pillow in, settle the corners and look at the closure. If a zipper strains or an envelope flap pulls open, the case is too tight for that pillow. If the pillow slides around and the tail flops past the end, it is too loose.
One extra detail that rarely gets mentioned: measure the thickness too. A very full pillow with the same footprint as a flatter one will take up more of the case. If your pillow is lofty, give yourself a little more width rather than less.
Open end, envelope or zipper: how the closure changes fit
The closure decides how much of the case's length is actually holding the pillow. We covered how each style feels against the face in our post on choosing a percale pillowcase, so this table sticks to fit.
| Closure | How it holds the pillow | Fit you can expect | Good for |
|---|---|---|---|
| Open end with hem | Extra length hangs past the pillow | Relaxed, a little loose at the end | Quick bed changes and pillows of slightly different sizes |
| Envelope flap | An inner pocket tucks over the end | Closer, tidier finish with no tail | People who want a hotel look without hardware |
| Hidden zipper | Fully closes around the pillow | Snug, the pillow cannot slide out | A base layer that protects the pillow itself |
Envelope cases are the ones we reach for when a pillow is a little short for its case. The flap takes up the spare length, so you get a neat end instead of a loose hem. The trade-off is that the flap only works if the pillow is long enough to reach it.
Zippered covers need the most accurate sizing. There is no spare tail to absorb a mistake, so a cover that is too small will not close, and one that is too large will let the pillow drift inside.
Should a pillowcase be loose or snug?
Somewhere in between, and it comes down to the pillow. A soft, squashy down alternative pillow likes a little room so the fill can move and recover its shape. A firmer, fuller pillow looks best in a closer fit that does not wrinkle at the sides.
Too tight causes real problems. It presses the loft down, so the pillow feels flatter than it is. It also puts strain on seams and zippers, which is where wear shows first. Too loose is mostly a comfort issue: the spare fabric bunches under your cheek and you end up straightening it every night.
If you are stuck with a case that is too long, fold the tail under the pillow rather than tucking it inside. It lies flatter and you will not feel a ridge.
People who sew sometimes shorten the case with one straight seam, which works well on plain cotton.
Do pillowcases shrink after washing?
Cotton ones can, yes. Woven cotton can tighten up when it is washed and dried, which is why the same extension guide tells home sewers to wash fabric before cutting so the shrinkage happens first. A ready-made case does not get that step from you, so the first few washes are when you will notice any change. A quick pillowcase size guide rarely mentions it, but it can turn a good fit into a tight one.
Heat is the main thing to watch. Hot water and a high dryer setting are hardest on cotton, and they are also hardest on the stitching around zippers. Our cotton percale cover's product page gives a care routine that suits most cotton cases:
- Machine wash warm or cold on a gentle cycle with a mild detergent.
- Tumble dry on low heat. Wool dryer balls help shake out wrinkles.
- Skip chlorine bleach and fabric softener, which coat cotton fibers.
A practical tip: if a case is already a close fit when new, take it out of the dryer while it is still slightly damp and put it straight back on the pillow. The cotton settles around the shape as it finishes drying, and it is far easier than wrestling a dry, crisp case over a full pillow.
Fitting a case over a protector or zip cover
Many people use two layers: a zip cover that stays on and a pillowcase on top that gets washed more often. Each layer adds a little bulk, so the top case needs some spare room. This is one place where an open end or envelope case is easier than a second zippered one.
Size the base layer to the pillow first, then the case to the pillow plus cover. Our cotton percale pillow cover with a hidden zipper is offered in Standard (18 by 26 inches) and Queen (20 by 30 inches) options, made from 100% combed long-staple cotton with the zipper tucked along the seam so you do not feel it.
Notice the Standard width there. Our standard pillow is 18 by 26 inches, a little narrower than the common 20 by 26 inch reference. That is worth knowing if you pair it with a case from another brand: a typical standard case will have some spare room along the sides.
The washable siliconized microfiber pillow comes in Standard (18 by 26), Queen (20 by 30) and King (20 by 36). Its own shell is a 233 thread count cotton percale, and the product page says it can be machine washed cold on a delicate cycle and tumble dried on low. If a case or cover does not suit your pillow, eligible items can be returned within 30 days of delivery under our 30-day return policy.
You can see the full range of hotel-quality pillows and bedding on our home page if you want to match a pillow and cover at the same time, using this pillowcase size guide as your checklist.
Frequently Asked Questions about pillowcase sizes
Are all pillowcases the same size?
No. The names are shared, but finished sizes vary by maker, closure and region. Two "standard" cases can differ by a few inches in length, so use a pillowcase size guide for the label and the listed measurements for the final call.
What does "standard/queen" on a pillowcase label mean?
It means one case is cut to cover both sizes, usually long enough for a 20 by 30 inch queen pillow. On a 20 by 26 inch standard pillow it will leave a loose tail you can fold under.
How much bigger should a pillowcase be than the pillow?
There is no fixed rule. A traditional open end case is often several inches longer and only slightly wider than its pillow, while envelope and zippered cases sit much closer to the pillow's own size.
What size pillowcase fits a 20 by 30 pillow?
A queen case, or a case sold as standard/queen. Check that the listed length is long enough for the pillow plus the closure, especially with envelope styles.
Can I put a king pillowcase on a queen pillow?
Yes, it will cover it. A king pillow is 6 inches longer than a queen, so expect at least that much spare fabric. Fold the extra under the pillow so it does not bunch under your head.
Do envelope pillowcases fit tighter than open end ones?
Usually, yes. The inner flap holds the end of the pillow, so there is no hanging tail. That makes accurate sizing more important, because a pillow that is too short will not reach the flap.
Can cotton pillowcases go in the dryer?
Most can, on low heat. High heat is what tends to shrink cotton and stress seams, so follow the care label and lift the case out before it is bone dry.
What size cover do I need for an 18 by 18 or 20 by 20 pillow?
Those are square throw pillow sizes, and they need a square cover labeled for that exact size. A rectangular bed pillowcase will not fit them neatly.
