Bhutanese currency (BTN) is called Ngultrum or Nu. A sub-currency is known as Chhertum. 1 Nu is equal to 100 Chhertum (Ch). Coins are used in Bhutan but they are not very popular. The coins come in 5 Ch, 10 Ch, 25 Ch, 50 Ch and 1 Nu denominations. Ngultrum or currency of Bhutan is officially pegged to Indian Rupee (INR) and trades at par with it. Thus, 1 Nu is equal to 1 INR. Indian Rupee is as readily accepted all over Bhutan as the Ngultrum. Though, American Express card is acceptable in the country, it can be used in very limited service establishments while other cards are still not accepted in Bhutan. Western Union Wire service is available at the post office of most towns in Bhutan but the process can be very slow and stretched out. Only the cities of Paro and Thimphu seem to have quick access to the Western Union computer system.
You may exchange US dollars and traveller's cheques at Paro Airport on arrival, banks in Thimphu (during the banking hours of 10:00 am to 1:00 pm from Monday to Friday) and the counters in the larger hotels. The best way is to bring a mixture of cash and travelers cheques in major currencies such as USD, CAD, EUR or AUD to be exchanged here. Carry a mixture of large and small denominations in cash so you do not have to loose money because you couldn’t get the change. Since, all meals are already included in the paid-for itineraries, the only expenses the tourists need to make are the personal expenses that can include drinks, laundry and shopping. While everyone may have a different idea on how much to spend and what to buy, usually, tourists end up shopping more than they had intended. Expenditure of 8 to 10 USD is normally expected.
Bhutan has a cash economy. Large hotels and major handicraft emporiums only accept credit cards, but they do incur a service charge. It is not possible to do ATM withdrawals and Credit card cash advances in Bhutan. BTN is not exchanged outside Bhutan but you can exchange your excess BTN for USD on departure, if you can produce the original exchange receipts. There is an American Express office in the capital and Amex is accepted in a few rare instances. At Thimphu, getting the money exchanged can be a very slow process, so get all the money you will need exchanged at once. Remember that your accommodation, meals and transportation is already paid for, so you need money only for buying souvenirs and other personal expenses. So, too much of BTN may result in your taking back souvenir cash later