Cost by tag

Open Cost by tag in Strays

Cost by tag shows what each owner, team and project spends on AWS each month, and how much spend has no tag at all. That untagged spend is the number to drive down: nobody is accountable for it. It is on the Cost by tag page, under Tags and costs.

Activate your tags first

AWS only splits spend by a tag after you activate it as a cost allocation tag. Strays can't do this for you: it only reads. Until you do, the page says the tag is probably not activated.

1. Sign in to the AWS console with the account that pays the bill. In an AWS Organization that is the management account; member accounts can't activate tags.
2. Open Billing and Cost Management, then Cost allocation tags in the left menu.
3. On the User-defined cost allocation tags tab, tick the keys Strays shows (for example Owner, CostCentre and Project). A key only appears once a resource has that tag, and tag keys are case sensitive.
4. Choose Activate.

It takes up to 24 hours for a tag to start counting, and Strays checks once a day, so allow up to two days. It is not retroactive: spend from before you activated a tag is never split by it, and shows as untagged. If you tagged resources long ago, the history stays untagged and only the months since fill in.

What you see

• Untagged spend for the month so far, as an amount and a percentage of your spend, with the last three months beside it. Lower is better.
• Spend by tag value (for example by each Owner), for the last three full months and this month so far, for all accounts together or one account.
• A CSV with every tag value by month, for all accounts together and then each account.

Strays uses the required tags in your tag policy, except Environment (it says what a resource is for, not who pays), up to three. Until you set a policy that is Owner, CostCentre and Project.

Why a tag shows no spend

• The tag isn't activated yet, or was activated in the last day: follow the steps above and wait.
• No resource carries the tag, or the key is spelt differently (owner is not Owner).
• The AWS accounts are billed through another account's consolidated bill: activate the tags there.
• The role is older than this feature. Update the strays-audit stack to the latest template; it adds one read-only permission, ce:ListCostAllocationTags, to see which tags are activated.

Cost to you

Strays asks Cost Explorer once a day for each tag key, per account. AWS charges $0.01 for each request, to the account: up to three keys is about $0.90 a month per account. Figures are unblended costs and can lag by up to a day. Amounts are in the account's billing currency; accounts billed in another currency than the first are left out of the totals.

Cost by tag is on the Business plan, and during the trial. (The tagging report and asset register are on Team.) Everyone in your organisation can read it.