When a product provider quotes an interest rate, it is not always immediately impressed by how much you will be paying – or be paid – if you take out the product.
Finance firms love selling complex products. That way customers do not know what they’re buying, will not understand the potential downside risks or realize the true costs, many of which will be expertly hidden in the small print.
Let’s get to this 2 terms.
Annual Percentage Rate (APR)

 Also known as nominal rate or simple interest rate per annual

 Does not take into account the effect of intrayear compounding

 Quoted by a financial institution when they lend out money, hence the alert interest from customers.

 The primary reason is to give customers the impression it costs less to borrow

 Normally applicable to loans, mortgages and credit cards

 APR is always effectively lower than the quoted AER
 APR to AER conversion mathematical equation: AER = (1 + APR / n) ^ n – 1
Annual Effective Rate (AER)

 Also know as Effective Annual Rate (EAR), Annual Percent Yield (APY) per annual

 Takes into account the effect of intrayear compounding

 Quoted by a financial institution when customers deposit money, hence paying interest to customers.

 The primary reason is to give customers the impression customer deposits earns more interests

 Normally applicable to savings accounts, fixed deposits.

 AER is always higher than quoted APR if there is 2 or more intrayear compounding. The only time when AER = APR is when there is no intrayear compounding,

 AER to APR conversion mathematical equation: APR = n [(AER + 1) ^ (1 / n) – 1], where n = number of times for intrayear compounding
APR – The Real Cost of Credit Card Annual Interest Rate
Assume you are one of those who constantly spends more than you earn and frequently misses your payment, putting yourself in Tier 3 interest charge bracket of 17.5% per annual.
Say, you have an outstanding balance of $ 10,000, so you’ll think (I did previously) that, even if I do not pay a single cent for the next 12 months, by the 13th month, I would need to pay 117.5 % x 10,000 = $ 11,750. Or, you think, every month, I will be charged a monthly interest of 17.5% / 12 = 1.4583%
Not quite that simple. Confused? Let’s solidify the concept with an example below.
Remember, you get your credit card statement monthly – your outstanding balance plus interest incurred previously will be transported forward to the outstanding month. That means the compounding period is monthly!
In other words, as you are well aware, for the first month, the outstanding balance plus interest incurred is $ 10,145.83. On the second month, the 1.4583% interest will be charged on $ 10,145.83 brought forward from the first month. See the impact of compounding over here?
Effectively, once you want to settle the balance outstanding after the 12th month, you will be paying MORE than the advertised interest rate of 17.5% due to compounding, because 17.5% is really the APR!
The actual interest rate you will be paying is the AER. For APR of 17.5%, the AER is 18.974% !! See APR to AER conversion equation above. Or in monetary amount, $ 11,897.40 instead of $ 11,750.00
Still, do not believe me? Compute FV in Excel with the following inputs: never = 12 months, 0.014583 for rate and PV = 10,000. Put zero for Pmt. The concept is similar.
So, why banks quoted you 17.5%?
Simple, because it is a lower number between the two. When you are the bank’s debtor, the bank needs you to give you the disguised impression that you need to pay less than you are actually paying. This is marketing – they are not actually lying to you, just that it’s not the whole truth. You have nothing to blame but your own ignorance.
Different countries have different rules and regulations in place to combat some of the unscrupulous activity surrounding quoting rates that have arisen in the past; however, there is no better insulator against these ruses than proper financial knowledge.
If you know of any bank which quotes AER instead of APR for credit card interests, let me know – I am pretty sure their credit cards product would not be selling too well even though they are telling the truth to customers!
AER – Truth Revealed! Fixed Deposits Annual Interest Rate
Assume $ 30,000 placed as Fixed Deposit for the period of 1 month, with advertised 3 percent interest per annual. Principal and interest will be credited to the savings account after maturity.
Your earned interest would be $ 73.97 by the end of the month
Did you ask, why? If it’s 3% per annual, monthly interest rate based on principal of $ 30,000 should (3/12)% x 30,000 = RM 75.
The truth here is that 3% annual rate is actually AER, which is your total return based on $ 30,000 if and only if your monthly interest earned is added into your initial principal, and gets carried forward to a month, for a total of 12 months repetitively.
Using FV function in Excel, where nper = 12, i = 0.00246625 and PV = 30,000, you get FV = 30,900.00.You earn interest of RM 300, which is 3% of the principal.
In other words, you only earn the quoted 3% per annual if and only if your monthly interest is added to the principal and transported forward to the twelve months for 12 months.You DO NOT actually receive 3% per annual out of your principal if the monthly interest is credited to your savings account every month for 12 months.
Example, 73.97 x 12 = 887.64. This is only 2.959% of 30,000!
Now using AER to APR conversion formula above, you get APR = 2.959%, which is exactly 887.64 over 30,000.
In this scenario, it is in the bank’s best interest to quote you the AER, instead of APR. They know that when you are the lender, you are seeking the highest rate of interest possible to entice you.
Feeling cheated? Yes. Dubious marketing? Double yes. Why can not they just present the facts just as it is? How many of nonpersonalfinancesavvy people know about this?
Here’s a quote I read somewhere:
Other industries look after loyal customers. Banks do the reverse; rewarding new customers with the best deals while neglecting their existing ones, regardless of how long you have banked with them.
* AER and EAR are essentially synonymous. EAR is a term adopted for overdraft calculation.
Source by Ching Foo Lieu