AAoA factors ALL OC accounts, open or closed, good and bad. It does not include CAs or PRs.
Take the open date listed on the CR, month and year, and calculate how many months the account has been opened through this month. Add the sum of all months and divide it into the number of OC accounts reporting. Convert your months into years and round down to the nearest whole number to get your CR's AAoA.
So, if a Visa was opened in 11/2002, a MC in 2/1996, a Discover in 6/2009, and a Verizon charge-off opened in 6/2004, then the ages in months are 80, 161, 2, and 62. The sum of these is 305. 305 divides by 4 accounts is 76.25 months or 6 years and roughly 4 months. FICO would read it as a 6 yr AAoA with it turning to 7 in 8 months.
I always check my CR at the first of each month as each account turns one month older. This month, my Excel spreadsheet showed my 2.9 AAoA turning to 3 yrs as of the first. Sure enough, like clockwork, AAoA turned 3 yrs.
