Personalized or Personalised? Decoding the Global Spelling Split

Have you ever typed a word, looked at it, and wondered if the red squiggly line beneath it was trying to trick you? If you’ve ever hesitated between personalized (with a z) and personalised (with an s), you aren’t alone.

This minor spelling variation is one of the classic flashpoints between American and British English. But don’t worry—the secret to mastering it is much simpler than you might think.

The Short Answer

Both spellings are 100% correct. Neither one is a typo or a spelling mistake.

• Personalized is the standard spelling in American English (US).
• Personalised is the standard spelling in British English (UK), as well as in Canada, Australia, New Zealand, South Africa, and many other countries influenced by British spelling conventions.

Why Is There a Difference?

The split comes down to a deliberate linguistic choice made centuries ago.

In the early 19th century, American lexicographer Noah Webster set out to reform American English spelling to make it simpler, more phonetic, and distinct from British English. One of his key changes was favoring the suffix -ize over the British -ise for verbs derived from Greek roots (like organize, recognize, and realize).