Locals or foreigners are not allowed to carry hefty sum of foreign currency without supportive documents and source. Therefore, we recommend travelers to carry only what they require. Kathmandu and major cities as well as some places at trekking route have bank counters and ATM Machines. You can easily withdraw cash in local currency.
You can exchange foreign currency at Money Exchange or banks. Most used and widely acceptable currency is American Dollar. Other commonly accepted currencies in Nepal are Pounds, Euros, Canadian dollar, Singaporean dollar, Ringgit, Yuan, Yen, Australian dollar, Indian Rupees etc.
If you wish to pay for your trip via Credit Cards then about 3 % of service charge is applicable.