The official currency in Bhutan is the Ngultrum, officially equivalent to Indian Rupee, which also circulates throughout Bhutan except Rs 500 and Rs 1000 currency notes. 

At the time of writing (December 2013), the exchange rate is $ 1 USD = 62 BTN and 1 EURO = 84 BTN (but please be aware that the daily exchange rate varies significantly).

Credit Cards have limited acceptability and payment by credit card is accepted mainly at deluxe hotels and a few selected handicrafts stores. There are ATMs in Bhutan but it usually operates only with their respective Bhutanese banks. Since these ATMs do not function with outside banks, ATM facilities cannot be used by visitors. Traveler's checks and cash are the best options if you need additional money.