The currency exchange for dollars to riel is normally around 4,000 KHR to 1 dollar, a dramatic devaluation since its first introduction in 1953. This does vary from place to place, and some money changers will give as much as 4,100 riel to the dollar. Currency can be changed in almost every bank in Cambodia, and many shops, travel agents, and hotels will also change money for you. However, this is not really necessary in most tourist places as the dollar is accepted almost everywhere and it is hard to get the riels changed back into dollars, and impossible once you leave the country.

It should also be noted that ripped or damaged US dollar bills will usually not be accepted by many shops and banks, and you should reject any damaged or torn bills you get given as change or in money changing. Travelers checks can be exchanged in most banks, although there is usually a 2-4 percent charge. If you are not traveling from the US or do not have dollars as currency, you can change your own currency bills for dollars once you arrive. Banks will charge a fee, and do not always give the best rates. It is advisable to shop around, and the best option is to change larger amounts for small bills in US dollars, as you get a better rate the more you change.

ATMs
There are ATMs in all the major cities across Cambodia, and they all dispense either dollar bills or Cambodian riel. ATMs are the easiest way to withdraw money from a foreign bank account while in Cambodia, and there is normally a fee of two to four dollars per transaction, so it is best to use them for larger withdrawals only.

Credit Cards
There are very few places in Cambodia that accept credit cards. They are usually only used in big hotels and the larger restaurants in Phnom Penh and Siem Reap. Outside these places, they are generally not accepted.

The U.S. Dollar
In many rural areas of Cambodia, the riel is used for all purchases, both small and large. However, the U.S. Dollar is widely used in the country, and its use in purchases of larger items or hotel bills is encouraged by the government. The use of the dollar started in the early 1980s, and continued through the 1990s as the United Nations sent dollars as humanitarian aid to the Cambodian government and UN personnel stationed in Cambodia spent their money in US dollars. Currently, payment for a tourist visa in most places is required in US dollars.

The Thai Baht
As well as Dollars and riel, the Thai Baht is also commonly used in areas along the border with Thailand, and it is common for foreign travelers entering Cambodia across this border to pay for their visas in Thai baht. Excess baht brought across the border by foreign travelers and merchants is able to be used in many areas such as Battambang and Pailin.