There are several areas in which British and American spelling are different. The differences often come about because British English
tends to keep the spelling of words it has absorbed from other languages (e.g. French), while American English has adapted the spelling to reflect the way that the words actually sound when they're spoken.
If you're writing for British readers, you should only use British spellings. In one or two cases, the preferred American spellings are acceptable in British English as well, especially the -ize/-ization endings. While you can use both the -ise/-isation or the -ize/ization endings in British English, it's important to stick to one style or the other throughout the same piece of writing.
Here are the main ways in which British and American spelling are different.
Words ending in –re
British English words that end in -re often end in -er in American English:
Words ending in -our
British English words ending in -our usually end in -or in American English:
Words ending in -ize or -ise
Verbs in British English that can be spelled with either -ize or -ise at the end are always spelled with -ize at the end in American English:
Words ending in -yse
Verbs in British English that end in -yse are always spelled -yze in American English:
Words ending in a vowel plus l
In British spelling, verbs ending in a vowel plus l double the l when adding endings that begin with a vowel. In American English, the l is not doubled:
Words spelled with double vowels
British English words that are spelled with the double vowels ae or oe are just spelled with an e in American English:
Note that in American English, certain terms, such asarchaeology, keep the ae spelling as standard, although the spelling with just the e (i.e. archeology) is usually acceptable as well.
Nouns ending with –ence
Some nouns that end with -ence in British English are spelled -ense in American English:
Nouns ending with –ogue
Some nouns that end with -ogue in British English end with either -og or -oguein American English:
The distinctions here are not hard and fast. The spelling analogue is acceptable but not very common in American English; catalog has become the US norm, but catalogue is not uncommon; dialogue is still preferred over dialog.
Aside from spelling differences, many items and practices have different names in British and American English. To explore further, see British and American terms.