AWS Billing and Cost Management
User Guide (Version 2.0)

Setting Up Your Monthly Cost Allocation Report

Setting Up a Monthly Cost Allocation Report

The cost allocation report includes the same line items as the detailed billing report (see Understanding Your Usage with Billing Reports), plus additional columns you've selected to include in the report identified by your tag keys.

By default, new tag keys that you add using the API or the AWS Management Console are automatically excluded from the cost allocation report. You can add them using the procedures described in this topic.

When you select tag keys to include in your cost allocation report, each key becomes an additional column that lists the value for each corresponding line item. Since you might use tags for more than just your cost allocation report (e.g., tags for security or operational reasons), you can include or exclude individual tag keys for the report. This ensures that you're seeing meaningful billing information that helps organize your costs. A small number of consistent tag keys makes it easier to track your costs. For more information, see Viewing a Cost Allocation Report.

To create the keys that appear in the cost allocation report

  1. Sign in to the AWS Management Console and open the Billing and Cost Management console at

  2. Select Preferences on the navigation panel on the left.

  3. For Receive Billing Reports, type a valid Amazon S3 bucket name and then choose Verify.

  4. Underneath the Detailed Billing Reports selection grid, choose Manage report tags, as shown in the following image:

  5. The page displays a list of tags you've created using either the API or the console for the applicable AWS service. Tag keys that currently appear in the report are selected, while the check boxes for excluded tag keys are cleared. Use the Search drop-down box to switch display excluded tags, as shown in Step 5.

    Cost Allocation Management page
  6. Select Excluded Tags in the Search column.

    Select any check boxes for tags that you want to add to the report.

    Cost Allocation Management Excluded keys
  7. Choose Save after you make your changes.

For Consolidated Billing customers, your cost allocation report includes all the usage, costs, and tags for your linked accounts. By default, all keys registered by linked accounts where you are the payer are available for you to include or exclude from your report. The detailed billing report with resources and tags also includes any cost allocation tag keys that you select using the preceding steps.

Getting an Hourly Cost Allocation Report

The cost allocation report is one of several that AWS publishes to an Amazon S3 bucket several times a day.


During the current billing period (monthly), AWS generates an estimated Cost Allocation Report. The current month's file is overwritten throughout the billing period until a final report is generated at the end of the billing period. Then, a new file is created for the next billing period. The reports for the previous months will remain in the designated Amazon S3 bucket.

Viewing a Cost Allocation Report

The following example tracks the charges for several cost centers and applications. Resources (such as Amazon EC2 instances and Amazon S3 buckets) are assigned tags like "Cost Center"="78925" and "Application"="Widget1". In the Cost Allocation Report, the user-assigned tag keys have the prefix "user", such as "user:Cost Center" and "user:Application". AWS-assigned tag keys have the prefix "aws". The keys are column headings identifying each tagged line item's value, such as "78925".

Keys in the Downloadable Report

You can use a desktop spreadsheet application to create pivot tables that group the keys and the values for each key so you can see combined values for tagged resources. The following example organizes information first by "Cost Center" and within each cost center further organizes the information by the "Application" tag.

An Example of a Microsoft Excel Pivot Table using tagged resources

Pick your keys carefully so you have a consistent hierarchy of values; otherwise, your report won't aggregate costs effectively, and you'll have many line items.


If you add or change the tags on a resource part way through a billing period, costs will be split into before and after the update as two separate lines in your Cost Allocation Report.

Unallocated Resources in Your Report

Any charges that cannot be allocated by tags in your Cost Allocation Report default to the standard billing aggregation (organized by Account/Product/Line Item) and are included in your report. Situations where you can have unallocated costs include:

  • You signed up for a Cost Allocation Report mid-month.

  • Some resources aren't tagged for part, or all, of the billing period.

  • You are using services that currently do not support tagging.

  • Subscription-based charges, such as Premium Support and AWS Marketplace monthly fees, cannot be allocated.

  • One-time fees, such as Amazon EC2 Reserved Instance upfront charges, cannot be allocated.

  • Amazon Elastic Block Store (Amazon EBS) snapshot charges cannot be allocated, even though Amazon EBS volume charges can be allocated.