An automated teller machine or automatic teller machine^[1][2][3] (ATM, American, Australian, Singaporean, Indian, Maldivian,Hiberno and Sri Lankan English), also known as an automated banking machine (ABM, Canadian English), cash machine,cashpoint, cashline, or colloquially hole in the wall (British and South African English), is an electronic telecommunications device that enables the customers of a financial institution to perform financial transactions without the need for a human cashier, clerk or bank teller.

On most modern ATMs, the customer is identified by inserting a plastic ATM card with a magnetic stripe or a plastic smart card with a chip that contains a unique card number and some security information such as an expiration date or CVVC (CVV). Authentication is provided by the customer entering a personal identification number (PIN).

Using an ATM, customers can access their bank deposit or credit accounts in order to make a variety of transactions such as cashwithdrawals, check balances, or credit mobile phones. If the currency being withdrawn from the ATM is different from that in which the bank account is denominated the money will be converted at an official exchange rate. Thus, ATMs often provide the best possible exchange rates for foreign travellers, and are widely used for this purpose.^[4]