What's the differnce between a credit and a debit card?

A credit card is a system of payment named after the small plastic card issued to users of the system. A credit card is different from a debit card in that it does not remove money from the user's account after every transaction. In the case of credit cards, the issuer lends money to the consumer (or the user) to be paid to the merchant. It is also different from a charge card (though this name is sometimes used by the public to describe credit cards), which requires the balance to be paid in full each month. In contrast, a credit card allows the consumer to 'revolve' their balance, at the cost of having interest charged. Most credit cards are the same shape and size, as specified by the ISO 7810 standard. The most common credit card size, known as ID-1, is 85.60 Ã— 53.98 mm.
A user is issued credit after an account has been approved by the credit provider, and is given a credit card, with which the user will be able to make purchases from merchants accepting that credit card up to a pre-established credit limit. Often a general bank issues the credit, but sometimes a captive bank created to issue a particular brand of credit card, such as Chase, Wells Fargo or Bank of America, issues the credit.

When a purchase is made, the credit card user agrees to pay the card issuer. The cardholder indicates his/her consent to pay, by signing a receipt with a record of the card details and indicating the amount to be paid or by entering a Personal identification number (PIN). Also, many merchants now accept verbal authorizations via telephone and electronic authorization using the Internet, known as a 'Card/Cardholder Not Present' (CNP) transaction.

Electronic verification systems allow merchants to verify that the card is valid and the credit card customer has sufficient credit to cover the purchase in a few seconds, allowing the verification to happen at time of purchase. The verification is performed using a credit card payment terminal or Point of Sale (POS) system with a communications link to the merchant's acquiring bank. Data from the card is obtained from a magnetic stripe or chip on the card; the latter system is in the United Kingdom commonly known as Chip and PIN, but is more technically an EMV card.

Other variations of verification systems are used by eCommerce merchants to determine if the user's account is valid and able to accept the charge. These will typically involve the cardholder providing additional information, such as the security code printed on the back of the card, or the address of the cardholder.

Each month, the credit card user is sent a statement indicating the purchases undertaken with the card, any outstanding fees, and the total amount owed. After receiving the statement, the cardholder may dispute any charges that he or she thinks are incorrect (see Fair Credit Billing Act for details of the US regulations). Otherwise, the cardholder must pay a defined minimum proportion of the bill by a due date, or may choose to pay a higher amount up to the entire amount owed. The credit provider charges interest on the amount owed (typically at a much higher rate than most other forms of debt). Some financial institutions can arrange for automatic payments to be deducted from the user's bank accounts, thus avoiding late payment altogether as long as the cardholder has sufficient funds.

Credit card issuers usually waive interest charges if the balance is paid in full each month, but typically will charge full interest on the entire outstanding balance from the date of each purchase if the total balance is not paid.

For example, if a user had a $1,000 transaction and repaid it in full within this grace period, there would be no interest charged. If, however, even $1.00 of the total amount remained unpaid, interest would be charged on the $1,000 from the date of purchase until the payment is received. The precise manner in which interest is charged is usually detailed in a cardholder agreement which may be summarized on the back of the monthly statement. The general calculation formula most financial institutions use to determine the amount of interest to be charged is APR/100 x ADB/365 x number of days revolved. Take the Annual percentage rate (APR) and divide by 100 then multiply to the amount of the average daily balance (ADB) divided by 365 and then take this total and multiply by the total number of days the amount revolved before payment was made on the account. Financial institutions refer to interest charged back to the original time of the transaction and up to the time a payment was made, if not in full, as RRFC or residual retail finance charge. Thus after an amount has revolved and a payment has been made that the user of the card will still receive interest charges on their statement after paying the next statement in full (in fact the statement may only have a charge for interest that collected up until the date the full balance was paid...i.e. when the balance stopped revolving).[1]

The credit card may simply serve as a form of revolving credit, or it may become a complicated financial instrument with multiple balance segments each at a different interest rate, possibly with a single umbrella credit limit, or with separate credit limits applicable to the various balance segments. Usually this compartmentalization is the result of special incentive offers from the issuing bank, either to encourage balance transfers from cards of other issuers, or to encourage more spending on the part of the customer. In the event that several interest rates apply to various balance segments, payment allocation is generally at the discretion of the issuing bank, and payments will therefore usually be allocated towards the lowest rate balances until paid in full before any money is paid towards higher rate balances. Interest rates can vary considerably from card to card, and the interest rate on a particular card may jump dramatically if the card user is late with a payment on that card or any other credit instrument, or even if the issuing bank decides to raise its revenue.

Because of intense competition in the credit card industry, credit providers often offer incentives such as frequent flyer points, gift certificates, or cash back (typically up to 1 percent based on total purchases) to try to attract customers to their program.

Low interest credit cards or even 0% interest credit cards are available. The only downside to consumers is that the period of low interest credit cards is limited to a fixed term, usually between 6 and 12 months after which a higher rate is charged. However, services are available which alert credit card holders when their low interest period is due to expire. Most such services charge a monthly or annual fee.

Debit card
is a plastic card which provides an alternative payment method to cash when making purchases. In most cases: Physically the card is an ISO 7810 card like a credit card; however, its functionality is more similar to writing a cheque as the funds are withdrawn directly from either the cardholder's bank account (often referred to as a cheque card), or from the remaining balance on the card. In other cases: some cards are designed exclusively for use on the Internet, and so there is no physical card.[5][6] In potential cases, the card may be completely different compared to these two examples.

Depending on the store or merchant, the customer may swipe or insert their card into the terminal, or they may hand it to the merchant who will do so. The transaction is authorized and processed and the customer verifies the transaction either by entering a PIN or, occasionally, by signing a sales receipt.

In some countries the debit card is multipurpose, acting as the ATM card for withdrawing cash and as a check guarantee card. Merchants can also offer "cashback"/"cashout" facilities to customers, where a customer can withdraw cash along with their purchase.

The use of debit cards has become wide-spread in many countries and has overtaken the check, and in some instances cash transactions by volume. Like credit cards, debit cards are used widely for telephone and Internet purchases. This[citation needed] may cause inconvenient delays at peak shopping times (e.g. the last shopping day before Christmas), caused when the volume of transactions overloads the bank networks.

For consumers, the difference between a "debit card" and a "credit card" is that the former immediately deducts the balance from a checking or savings account, whereas the latter allows the consumer to spend money they might not actually have (but promise to pay later to the card-issuing bank).

In some countries: When a merchant asks "credit or debit?" the answer determines whether they will use a merchant account affiliated with one or more traditional credit card associations (Visa, MasterCard, Discover, American Express, etc.) or an interbank network typically used for debit and ATM cards, like PLUS, Cirrus (interbank network), or Maestro.

In other countries: When a merchant asks "credit or debit?" the answer determines whether the transaction will be handled as a credit transaction or as a debit transaction. In the former case, the merchant is more likely than in the latter case to have to pay a fee defined by fixed percentage to the merchant's bank. In both cases, the merchant may have to pay a fixed amount to the bank. In either case, the transaction will go through a major credit/debit network (such as Visa, MasterCard, Visa Electron or Maestro). In either case, the transaction may be conducted in either online or offline mode, although the card issuing bank may choose to block transactions made in offline mode. This is always the case with Visa Electron transactions, usually the case with Maestro transactions and rarely the case with Visa or MasterCard t