Charges for most AWS services are calculated over the course of the month and are billed together at the beginning of the following month.

Some services are charged to your default payment method when those services are activated, such as the initial charge for activating a Developer or Enterprise Support plan or a new Reserved Instance. These charges also appear on your monthly bill, but were already charged when the services were activated.

You receive a notification when your AWS bill is finalized around the first day of each month, and the bill is charged to your default payment method shortly thereafter (usually between the 3rd and the 5th of the month).

If you want to update the payment method associated with your AWS account before a new bill is charged, make sure to update it before the first of the month.