Each night we calculate the disk space used by our customers. If your account exceeds its allotted limited you will be charged for extra storage.
For every day that you exceed your storage quota you will be charged a prorated rate based on the monthly price.
For example if the price for excess storage is $0.10 / MB and you exceed your limit by 100 MBs for the entire month the cost would be $10. However if you exceeded your limit for only a single day the cost would be $0.33. The monthly cost per MB is divided by the number of days in the month giving a daily cost per MB. Your account will be charged this price each day you exceed your storage limit.