A standard pillowcase is usually about 20 inches by 26 inches, which is roughly 51 cm by 66 cm in the US, while many UK/European “standard” pillowcases are closer to 50 cm by 75 cm (about 20 inches by 30 inches).

Quick Scoop

  • In the US, a standard pillowcase is typically 20" x 26" (51 x 66 cm), and this is the most common size for twin, twin XL and full beds.
  • Some brands mention a “super standard” that runs a bit longer at about 20" x 28" (51 x 71 cm), but it’s still in the same general category and fits most standard pillows.
  • In the UK and much of Europe, what’s sold as a standard pillowcase is often around 50 x 75 cm (about 20" x 30"), so it’s slightly longer than the US version but intended for the same everyday use.

Mini notes

  • Always check the actual measurements on the packaging or product page if you’re buying online or internationally, since “standard” can vary a little by region and brand.
  • If your pillow is extra lofty or gusseted, sizing up by 1–2 inches in length can make it easier to slide on and help the case look smooth instead of overstuffed.

For most shoppers asking “what size is a standard pillowcase” , you’re looking at around 20" x 26" in the US and about 50 x 75 cm in the UK/Europe.

TL;DR:
Standard pillowcase = roughly 20" x 26" (51 x 66 cm) in the US and about 50 x 75 cm (20" x 30") in the UK/Europe, with minor variations by brand.

Information gathered from public forums or data available on the internet and portrayed here.