> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cloudcapital.co/llms.txt
> Use this file to discover all available pages before exploring further.

# 12-Month AWS Tag Backfill

> Activate tag backfill in the AWS Billing Console to apply your active cost allocation tags to 12 months of historical cost and usage data.

<Info>
  Time to complete: \~3 minutes · One-time setup · Audience: AWS payer account owner
</Info>

When you activate cost allocation tags in AWS, they only appear on cost data going forward. Historical spend — the data already in your Cost and Usage Report — remains untagged unless you explicitly trigger a backfill. This guide walks through the self-service tag backfill available directly in the AWS Billing Console.

Once complete, your full year of tagged spend flows into Cloud Capital's allocation, forecasting, and commitment planning.

<Note>
  This is a separate process from [requesting a CUR data backfill via AWS Support](/get-started/aws-cur-backfill). That process re-exports raw cost data for up to 36 months. This process re-applies your active cost allocation **tags** to existing CUR data — it takes \~3 minutes and requires no support case.
</Note>

***

## Steps

<Steps>
  <Step title="Open Cost allocation tags">
    Sign into the AWS Management Console as the payer account owner and navigate to **Billing and Cost Management**.

    In the left navigation, select **Cost allocation tags**.

    > Direct link: [console.aws.amazon.com/billing/home#/tags](https://console.aws.amazon.com/billing/home#/tags)

    You'll see a table of your User-defined and AWS-generated tags with their activation status. Confirm the tags you want backfilled are listed as **Active** — only active tags are included in the backfill.
  </Step>

  <Step title="Click Backfill tags">
    In the top-right toolbar of the Cost allocation tags page, click **Backfill tags**.

    <Note>
      This action is separate from the **Activate** button. You can trigger a backfill without re-activating tags — they just need to already be active.
    </Note>

    This opens the backfill range dialog.
  </Step>

  <Step title="Choose 12-month range and confirm">
    In the dialog, use the **Backfill start month** dropdown and select the option for **12 months prior** to the current month.

    The dropdown offers preset options (1 month, 3 months, 6 months, 12 months prior). Select **12 months prior** for the full year of historical data.

    Click **Confirm**.

    AWS will begin reprocessing your historical Cost and Usage Report data with your active cost allocation tags applied.

    <Info>
      Updated data typically appears in Cost Explorer and Cloud Capital within **24 hours**. Full reconciliation completes in **48–72 hours** depending on account size.
    </Info>
  </Step>
</Steps>

***

## What this unlocks

With 12 months of tagged historical data in place, Cloud Capital can:

* Attribute every line item to its owner, environment, and cost center from day one
* Build accurate year-over-year forecasts using fully tagged spend
* Size commitment recommendations against a complete picture of historical usage rather than partial, untagged data

***

## Frequently asked questions

<AccordionGroup>
  <Accordion title="Do I need to re-activate my tags before running the backfill?">
    No — tags just need to already be **Active**. If your tags are active, click **Backfill tags** directly. The backfill and activation flows are independent.
  </Accordion>

  <Accordion title="Can I run the backfill more than once?">
    Yes. If you activate additional tags later, you can return to this page and trigger another backfill to apply the new tags to historical data.
  </Accordion>

  <Accordion title="What IAM permissions are required?">
    The account owner or a user with billing console access can perform this action. If you're using fine-grained IAM billing permissions, the `billing:*` read and write actions cover this. See [Migrating to Fine-Grained IAM Policies](/get-started/aws-fine-grained-access-check) if you're unsure whether your account uses updated permissions.
  </Accordion>

  <Accordion title="What's the difference between this and the CUR backfill via Support?">
    These are two separate operations:

    |                  | Tag backfill (this guide)                       | CUR backfill via Support                     |
    | ---------------- | ----------------------------------------------- | -------------------------------------------- |
    | **What it does** | Re-applies active tags to existing CUR data     | Re-exports raw CUR data to your S3 bucket    |
    | **Time**         | \~3 min (self-service)                          | 24–48 hrs (support case)                     |
    | **Max history**  | 12 months                                       | 36 months                                    |
    | **When to use**  | Tags are active but historical data is untagged | You need more than the default history in S3 |

    For most customers, running the tag backfill is all that's needed. The [CUR backfill via Support](/get-started/aws-cur-backfill) is only required if you need more than 12 months of raw cost data in your S3 bucket.
  </Accordion>
</AccordionGroup>

***

<CardGroup cols={2}>
  <Card title="Map cloud resources" icon="diagram-project" href="/get-started/map-cloud-resources">
    Assign your AWS resources to cost layers for allocation and forecasting.
  </Card>

  <Card title="Request a CUR backfill (36 months)" icon="clock-rotate-left" href="/get-started/aws-cur-backfill">
    Need more than 12 months of raw cost data? Open an AWS Support case to backfill up to 36 months.
  </Card>
</CardGroup>