Originally Posted by
formercap1agent
Here's Capital One's policy on promotional rates. If you're more than 3 days past due while on the promo rate, the rate immediately goes to the non-promo rate (the rate it would have changed to after the promo ended). If you're past due a second time, or for more than 30 days, then you go to the default rate which is around 27%.
As for interest accruing, this will take a longer explanation. If you want to avoid paying any interest you will have to pay off the entire balance by the closing date of the very last statement before the promo ends. So let's say it's zero until April 1, and your statement date is the 15th. You actually have to pay it all off by March 15 not April 1.
Some think that because you have a zero rate, if you pay in full by the next due date it's zero interest. Not according to Cap1. They go by the strict rule of paying in full all the time, even if you're under a promo, to avoid finance charges. So, because you weren't paying in full during the promo, interest accrues immediately once the promo period ends (see above).
Hope this helps!