Annual percentage rate (APR) is calculated using simple
interest formula. Annual percentage yield (APY) is calculated using
compound interest formula. Due to this reason, APY will never be
less than APR.
When the APY is calculated with an interest compounding
annually, APY may equal APR. If the interest is compounding more
than once a year, then the value of APY will be greater than the
value of APR.
Lenders use annual percentage rate (APR), whereas borrowers use
annual percentage yield (APY). This can be seen while borrowing and
lending loans, credit cards etc.