British and American keyboards
There are two major English language computer keyboard layouts, the United States layout and the United Kingdom layout defined in BS 4822 (48-key version). Both are QWERTY layouts. Users in the United States do not frequently need to make use of the £ (pound) and € (euro) currency symbols, which are common needs in the United Kingdom and Ireland, although the $ (dollar sign) symbol is also provided as standard on UK and Irish keyboards. In Australia, New Zealand and English-speaking Canada, the US keyboard is used.
PC keyboards 
- There is 1 extra key in total (UK=62, US=61, on the typewriter keys)
- The Alt key to the right of the space bar is replaced by an AltGr key
- The # symbol is replaced by the £ symbol and a 102nd key is added next to the Enter key to accommodate the displaced #
- @ and " are swapped
- the ~ is moved to the # key, and is replaced by a ¬ symbol on the backquote (`) key
- the \ key is moved to the left of the Z key
- the Enter key spans two rows, and is narrower to accommodate the # key
On laptop computers, the | and \ key is often placed next to the space bar.
Early versions of Windows handled both the differences between the two keyboards and the differences between American English and British English by having two English language options — a UK setting and a US setting. While adequate for users in the United States, United Kingdom, and Ireland, this solution caused difficulty in other English-speaking countries. In many Commonwealth countries and other English-speaking jurisdictions (e.g., Canada, Australia, the Caribbean nations, Hong Kong, Malaysia, India, Singapore, New Zealand, and South Africa), local spelling conformed more closely to British English usage, while the supplied keyboard was printed with the United States layout on the keys. People in these countries were forced to choose between a keyboard layout incompatible with their hardware, or having their spell checker software flag the American English spelling of words such as "colour", "centre", etc.
However, in more recent editions, the number of options was increased, allowing users to select the correct keyboard and dialect independently. For example, one is given a number of default options for locality that will usually correctly match dialect and keyboard. Further, even if your hardware keyboard layout does not match the device driver software layout that was pre-selected, you can change that without changing the regional setting.
Since the standard US keyboard layout in Microsoft Windows offers no way of inputting any sort of diacritic or accent, this makes it unsuitable for all but a handful of languages unless the US International layout is used. The US International layout changes the `, ~, ^, " (for ¨), and ' (for ´) keys into dead keys for producing accented characters. The US International layout also uses the right alt (AltGr) as a modifier to enter special characters. Although there is no UK International layout on Windows, XP SP2 and above provide a UK Extended layout which, if activated, will allow the user to enter a wide variety of diacritics (such as grave accents) which are not accommodated by the standard UK layout.
Apple Macintosh keyboards 
The default US layout on Apple Macintosh computers has allowed input of diacritical characters since inception, whereby the entire MacRoman character set is directly available, so many of the problems outlined above are not encountered. However, Apple supplies a "British" keyboard layout with the following differences:
- the # symbol is replaced by the £ symbol (as on PC keyboards); the # is still available by pressing ⌥ Option+3
- more recent Apple British keyboards move the backquote/~ key to the left of the Z key and replace them with a section sign (§) and a plus-minus sign (±) respectively.
- the Enter key spans two rows and is shaped similarly to the Enter key of many non-US PC keyboards.
See also