The interest rate adjusted for intra-year compounding. Because interest on a mortgage is calculated monthly, a 6% mortgage actually has a rate of .5% per month. If there were no principal repayments the first year, $100 invested in a 6% mortgage would actually earn $6.17 of interest during the year because of reinvestment of monthly interest. The 'effective rate' is thus 6.17%, while 6% is termed the 'nominal' rate. Similarly, a 6% bond on which interest is paid quarterly has an effective rate of 6.14%.