Zillow Advice: Mortgage - What is the APR formula for ARMs? http://www.zillow.com/advice-thread/What-is-the-APR-formula-for-ARMs/381669/ Zillow Advice | Zillow Real Estate Given all the info you posted ... http://www.zillow.com/advice-thread/What-is-the-APR-formula-for-ARMs/381669/ Given all the info you posted is accurate, the only thing that can make the APR lower is if someone is using an index that is lower than yours. If you are using a 1 year Libor and someone else is using a 6 month Libor Index, then their APR will be lower ( that will be $50 advice fee). Hey, I dont know of any lenders doing 5/6's, do you? Thu, 20 Jan 2011 16:24:00 GMT http://www.zillow.com/advice-thread/What-is-the-APR-formula-for-ARMs/381669/ 2011-01-20T16:24:00Z ItIt &nbsp;may be the index.&nbsp; ... http://www.zillow.com/advice-thread/What-is-the-APR-formula-for-ARMs/381669/ ItIt &nbsp;may be the index.&nbsp; If you are quoting a Libor and others are quoting a TTreasury your APR will calculate higher. Thu, 20 Jan 2011 16:21:00 GMT http://www.zillow.com/advice-thread/What-is-the-APR-formula-for-ARMs/381669/ 2011-01-20T16:21:00Z http://www.mtgprofessor.com/tutorial_on_annual_percentage_rate_(apr).htmNot ... http://www.zillow.com/advice-thread/What-is-the-APR-formula-for-ARMs/381669/ <a href="http://www.mtgprofessor.com/tutorial_on_annual_percentage_rate_(apr).htm" rel="nofollow">http://www.mtgprofessor.com/tutorial_on_annual_percentage_rate_(apr).htm</a><br/><br/>Not sure if this will help but its a decent read. Thu, 20 Jan 2011 16:04:00 GMT http://www.zillow.com/advice-thread/What-is-the-APR-formula-for-ARMs/381669/ 2011-01-20T16:04:00Z