For most general purposes, there is little significant difference between British and American English in written texts. In practically all circumstances, any text written in standard British English will be comprehensible to an American reader, and vice versa.
British usage historically accepts both the -ise and -ize spellings, but the former is now more frequently used in a broad range of publications. Therefore, we recommend that the -ise, -yse and -isation forms be used, except where the context specifically requires American spelling.
The following summary lists the well-known and now commonly accepted distinctions in British/American spelling.
| British English | American English |
| -ce (defence) | -se (defense) |
| -isation (nationalisation) | -ization (nationalization) |
| -ise (realise) | -ize (realize) |
| -our (colour) | -or (color) |
| -re (centre) | -er (center) |
| -yse (analyse) | -yze (analyze) |
However, note that size and capsize are never written with –ise in British English.
Also, note that British usage has the form programme (as opposed to the American program) except when referring to computer code, in which case program is preferred.