AP style: Convert that currency
AP reminds us that it's probably a good idea to convert those rands, rupees and euros into dollars for a U.S. audience with a new stylebook entry:
Currency conversions are necessary in stories that use non-U.S. currency to make clear for readers how a number translates into dollars. But conversions should be used sparingly and preferably not in the lead unless it's a significant part of a story. A conversion is generally needed only the first time a currency is mentioned. The reader can make the necessary conversions after that.
Do not convert amounts that are not current because exchange rates change over time.
When conversions are needed, use the $ sign to report U.S. dollar amounts and the € sign for euros. ...
For all other currencies, following the amount, spell out the name of the currency followed in parentheses by the equivalent in U.S. dollars. Japan approved a 1.8 trillion yen ($18 billion) extra budget to partially finance an economic stimulus package.
When dealing with a dollar currency of a country other than the United States, use the following abbreviations before the amount on second and subsequent references:
AU$ Australian dollars
CA$ Canadian dollars
SG$ Singapore dollars
NZ$ New Zealand dollars
HK$ Hong Kong dollars
NT$ New Taiwan dollars
ZW$ Zimbabwe dollars