Creating cost categories - AWS Billing

Creating cost categories

Cost allocation helps you map and assign your AWS Cloud costs to the correct groups within your organization. To allocate these costs, create cost categories. Cost categories are composed of rules.

There are two types of rules:

  1. Rules to group costs

  2. Rules to split costs

Rules to group costs

Define rules to group costs by using one or more of the following dimensions:

  • Accounts

  • Cost allocation tags

  • Charge Type, such as credits and refunds

  • Service

  • Region

  • Usage Type, such as BoxUsage:t2.micro

Rules are evaluated in the order in which they're defined.

Example: Rules to group costs

Your engineering department has projects Alpha and Beta, and the marketing department has project Gamma.

All resources are tagged with the project name that they're used for, such as Project:Alpha, Project:Beta, or Project:Gamma.

You create a cost category named Department to allocate costs to the Marketing and Engineering departments. For the Department cost category, you define your rules as:

  • Rule 1: If a cost has a cost allocation tag of Project:Alpha or Project:Beta, then assign the cost to Department:Engineering.

  • Rule 2: If a cost has a cost allocation tag of Project:Gamma, then assign the cost to Department:Marketing.

You can also provide a default name for uncategorized costs. In this example, costs associated with untagged resources should be allocated to the IT department

  • Rule 1: If a cost has a cost allocation tag of Project:Alpha or Project:Beta, then assign the cost to Department:Engineering.

  • Rule 2: If a cost has a cost allocation tag of Project:Gamma, then assign the cost to Department:Marketing.

  • For all other costs, assign it to Department:IT.

In this example, the cost category name is Department. The cost category values are Engineering, Marketing, and IT.

Rules to split costs

Costs that are allocated to one cost category value can be split among others. In this example, if IT costs should be split between Engineering and Marketing departments in a 70:30 ratio, you can define a split charge rule to perform that allocation.

When you create your cost category, you can provide additional details such as:

  • Effective Date – Set the start date for your cost category. By default, this date will be set to the current month. If you choose a prior month, your cost category rules are then applied retroactively from that date.

  • Tags – To control access to who can edit this cost category, add a tag to the cost category. You then update your IAM policy to allow or deny access to that cost category. For example, you can add a tag Role:Administrator to your cost categories and then update an IAM policy to explicitly allow specific roles access to cost categories that have that tag.

Dy default, regular accounts and the management account in AWS Organizations have access to create cost categories.


To request a backfill of your cost data in your AWS Cost and Usage Report, create a support case. In your support case, specify the report name and the billing period that you want backfilled. For more information, see Contacting AWS Support.

Use the following procedure to create a cost category. After you create a cost category, wait up to 24 hours for your usage records to be updated with the cost category values.

To create a cost category
  1. Sign in to the AWS Management Console and open the AWS Billing and Cost Management console at

  2. In the navigation pane, choose Cost Categories.

  3. Choose Create cost category. You can use the cost preview panel as reference as you update your rules.

  4. Next to Group your costs, enter the name of your cost category. Your cost category name must be unique within your account.

  5. Use either the Rule Builder or JSON editor to define your cost categories.

    For more information about the JSON request syntax, see the Cost category section in the AWS Billing and Cost Management API Reference

  6. For Rule builder, choose Add rule.

  7. Choose Rule type, either Manually define how to group costs (Regular rule) or Automatically group costs by account or tag (Inherit rule).

  8. For regular rule, choose if your costs meets all or any of the conditions.

  9. Choose a billing Dimension from the list.

    1. For a regular rule type, you can choose Accounts, Service, Charge Type (for example, recurring reservation fee), Tag key, Region, Usage Type, or Cost Category. (You can choose Cost Category to create hierarchical relationships among your cost categories.)

    2. For an inherited value rule type, you can choose Account or Tag key (Cost allocation tags key).

  10. For a regular rule type, choose Operator from the dropdown list. Your options are Is, Contains, Starts with, and Ends with.


    Contains, Starts with, and Ends with are only supported with Accounts and Tag dimensions. If you use these operators with Accounts, the engine evaluates against account name, and not account ID.

  11. Choose a filtered value or enter your own value for your Dimension in the attribute selector.


    The Account dimension uses account names, not account IDs for the inherited cost category value.

  12. Choose Add a condition as needed and repeat steps 9 - 11.

  13. For Group costs together as, enter a cost category value.

  14. Choose Create rule.

  15. (Optional) Add a default value. It categorizes all unmatched costs to this value.

  16. (Optional) To rearrange the rule order, use the arrows or change the number on the top right of each rule.

    Rules are processed in order. If there are multiple rules that match the line item, then the first rule to match is used to determine that cost category value.

  17. (Optional) To remove a rule, select the rule and choose Delete.

  18. Choose Next.

  19. (Optional) To split your cost, choose Add a split charges. For more information about split charge rules, see Splitting charges within cost categories.

    1. Choose Add a split charge.

    2. Under Source value, choose your cost category value.

    3. Under Target values, choose one or more cost category values you wish to allocate split charges to.

    4. Under Charge allocation method, choose how you want to allocate your costs. Your choices are proportional, fixed, and even split.

    5. For fixed charge allocation, enter the percentage amount to allocate each target cost category value.

    6. Repeat step 19 as needed.

  20. Choose Next.

  21. (Optional) To add a lookback period for your cost category rules, choose the month from when you want to retroactively apply the rules.

  22. (Optional) To add a tag, choose Add new resource tag and enter a key and value.

  23. Choose Create cost category.

Understanding the cost preview panel

The cost preview panel shows you in real time how your costs group together or split apart as you create or update your cost categories rules. The results you see in the cost preview panel is an estimate based on your month-to-date net amortized cost.

Here are some things to keep in mind as you use the cost preview panel:

  • The cost preview results might not be accurate if your rules have complex conditions. For example, containing too many matched values with Contains, Starts With, Ends With operators.

    For a more precise results, save your rules and check the cost categories details page.

  • If your rules are too complex or takes too long to calculate in real time, the preview will not show a cost breakdown.