Reading a cloud bill: where the money usually hides and what to check before deleting

Start with where the money goes

Open the provider's cost tool and group the last full month by service, then by usage type within the largest service. On AWS, Cost Explorer shows up to thirteen months of history and its interface is free to use; other providers have similar reports or an exportable usage file. Write down the top three services and the share of the total each represents. A bill dominated by one line is a different problem from one spread over fifty small ones. Data in the current month is a day behind and excludes some adjustments, so use complete months for comparisons.

• Group by service, then usage type.
• Compare two complete months.
• Use net figures where discounts and credits matter.

Explain the increase before looking for savings

If the bill grew, find out when and in which line. A step change on a date usually matches a launch, a new environment or a changed setting, while a steady climb suggests growth in storage, data transfer or a resource that was never turned off. Ask the team what changed on that date. A saving that removes the thing that caused real revenue is not a saving. The review is as much about asking who needs each large line as about finding waste.

• Look for the date a line stepped up.
• Ask who owns each large resource.
• Separate growth in use from waste.

The usual quiet charges

Some charges persist after the thing that caused them is gone. An unattached storage volume stays and is charged until deleted, and AWS documents that a volume cannot be deleted while attached and that deletion destroys its data. Public IPv4 addresses are charged, including allocated Elastic IPs that are not attached to anything. Old snapshots, stopped servers that still have disks, oversized instances and test environments left running are the other common finds. Each can be listed with a read-only command or a console filter, which is why a review needs listings of the resources and not just the bill.

• Unattached volumes and old snapshots.
• Allocated but unused public addresses.
• Instances larger than their measured use.

Check use and back up before deleting

A resource that looks unused may be the only copy of something or may run a task once a quarter. Before removing anything, check recent activity with the metrics your provider keeps, ask the owner, and take a snapshot or backup where deletion would destroy data. Make one change at a time and watch the next bill and the application. Treat a saving as an estimate until the next bill confirms it, because credits, discounts and committed spend change the real figure.

• Check metrics and ask the owner.
• Snapshot first when data would be lost.
• Confirm the saving on the following bill.

What the fixed review adds

The cost review reads one month of one account's bill line by line, classifies each large line as needed, unclear or apparently unused with evidence, and ranks up to ten changes with the saving worked from your own figures, the risk and the way back. It never changes your account, does not guarantee a saving and gives no tax or accounting advice. Unclear lines are listed as unclear rather than recommended for deletion.