Recently I've been working towards planning my next App-O-Rama, and attempting to workout exactly how many credit inquires and account closures (by me) my credit report can take.

I've been monitoring my score and seeing it go back into the low 800's and I'm a bit confused on how average age of accounts is calculated. On one side sites like credit karma show the average age of open accounts. While I'm getting conflicting information elsewhere that suggests the average age of accounts is the average age for all open and closed accounts.

Anyone have a explanation?