Skip to main content

Amortized, Blended, and Unblended Costs

When configuring reports with AWS data, you have an option to show costs as amortized, blended, or unblended.

If you have consolidated multiple AWS accounts into a single billing account and have reserved instances that are shared across those accounts, you can view your costs on an unblended or blended basis.

  • Amortized

    Overview: A cost metric that represents the effective daily rate of upfront, prepaid fees, combined with monthly reservation fees, including applied discount rates, and spread across the billing period.

    Additional info:

    The Amortized view distributes any upfront fees and monthly installments evenly across the reservation period. Cost is presented on an accrual basis, as transactions are displayed as they occur, whether paid or not. This is useful because when you purchase EC2 reservations, your costs are recorded at the time they are charged. They’ll appear as a single charge on that day, distorting the scale of the cost axis. Because other EC2 usage costs can be so much lower than the reservation fees, they almost disappear from the chart and you won’t be able to see spending trends. To solve this problem, use the Amortized view.

    Calculation: [prepaid fees] + [reservations] ÷ [days in billing period]

    When to use: To see more accurate spending trends that include EC2 usage costs and reservation fees.

  • Unblended

    Overview: This cost metric displays the amount charged at the time of usage. (This is the default setting.)

    Additional info: Cost is presented on a cash basis, reflecting usage on the day it is charged. When grouped by charge type, unblended costs separate discounts into their own line items.

    Calculation: For each AWS resource, [applicable rates] x [usage]

    When to use: To view the amount of each discount received.

  • Blended

    Overview: This cost metric is based on the average rate for each instance type for all member accounts of an organization.

    Additional info: Blended costs are the averaged rates of the reserved and on-demand instances that are used by member accounts that are consolidated under a single billing account. The blended view recognizes relative usage of reserved instances. Accounts that make more use of reserved instances will be allocated a higher proportion of those overall costs. Note that if you only have one account, if you don’t have consolidated billing set up, or if you don’t use a reserved instance, then the blended and unblended costs will be the same and reflect the simple usage costs.

    Calculation: [combined rate for each service] x [an account's use of the service]

    When to use: To have a consolidated view of member accounts in an AWS parent organization.

For more information, see the AWS documentation and AWS blog.