Credit card interest rates are set yearly, but calculated monthly.  Some credit card interest may be calculated daily and charged monthly. For example, let's say your card has an APR of 18%.

If your total purchase is about RM100 with tax, it would cost you approximately an additional RM18 in interest if you choose to stretch your payments over a full year, and you do not charge additional purchases on top of your balance.  And if your card "compounds" the interest (a practice of charging interest on the monthly interest accrued), the total interest will be several dollars more than the annual rate.

To calculate your monthly interest charge, the bank takes the 18% APR and divides it by 12 months for the year.  That comes to 1.5% of the average daily balance for the month.

The average daily balance is a method of leveling out the amount you owe, which may fluctuate from day to day because of payment and purchases.  The calculations to determine average daily balance sound complicated, but they're really rather simple.

In effect, the bank adds together the balance on your credit card for each day of the month, and divides the total by 30, the number of days in the month.  For a more complete explanation of how the average daily balance is calculated, see the chart.

Yearly Rate = 18%
Monthly Rate = 1.5%
STATEMENT 1
(Based on a RM100 purchase on the first day of the billing cycle)
Previous/beginning balance = RM100
Balance subject to finance charge = RM0
Finance charge = RM0
Payment made 25 days into cycle = RM50
Ending balance = RM50
STATEMENT 2
Previous/beginning balance = RM50
Balance subject to finance charge
(RM100 x 25 days/30 days = RM83.33)
(RM50 x 5 days/ 30 days = RM8.33)
(RM83.33 + RM8.33 = RM91.66 or RM92) = RM92
Finance charge
(1.5% of RM92 = RM1.38) = RM1.38
Ending balance
(RM50 + RM1.38 = RM51.38) = RM51.38

Let's say you decide to pay the RM100 charge for your dress in two monthly payments of RM50.
You receive your credit card statement and see the charge listed.  Approximately three weeks after you receive your statement, you mail in your payment of RM50.  It arrives at your bank 25 days into your credit card cycle.  You make no additional charges and next month's credit card statement arrives.

You see your previous balance of RM50, an interest charge of RM1.38, a balance subject to finance charge of RM92, and an ending balance of RM51.38.  Meaning the total cost of purchasing the dress, assuming you pay the ending balance in full, is RM101.38.

But how did the bank arrive at RM1.38 in interest?

If you had paid the RM100 charge in full by the due date on the statement, you would have paid no interest, leveraging the bank's "grace period" - generally 14 to 25 days from the date of purchase.  But because you paid only RM50, interest is accrued from the date of purchase using the average daily balance method.

So in calculating the average of your account's daily balance, the bank looks at the number of days carrying any given balance.  Since your first RM50 payment was received 25 days into the credit card cycle, you carried a balance of RM100 for 25 days (RM100 x 25 days divided by 30 days in the month = RM83.33, the average daily balance for 25 days).

After your first payment was received, you then carried a balance of RM50 for the remaining five days in the month (RM50 x 5 days divided by 30 days in the month = RM8.33, the average daily balance for 5 days).

If you add both average daily balances from above, you get your balance that is subject to a finance charge of RM92.  Therefore, the 1.5% (the monthly interest rate) of RM92 is RM1.38, your interest charge.

Balance Transfer Schemes
Most banks in Malaysia offer balance transfer schemes. These differ among the different credit cards and different banks and are usually limited to the approved credit limit of cardholders.

Banks usually require that you maintain your credit card account with them for a minimum period of six months before you are allowed to transfer out the amount outstanding to another bank. Failing which, you will be charged interest on the transferred amount at between 13% and 15% per annum, calculated on a daily basis.