Pull a month of billing data from AWS, Azure, and Google Cloud and you get three files that describe the same thing three different ways. Same idea of "what did this cost," different column names, different definitions, different ideas about when a discount counts. Anyone who has tried to put those side by side knows the next step: a pile of mapping tables and a script that nobody wants to own.

That's the problem FOCUS was built to remove. Issue #5 mentioned it in passing. Here's the plain version.

What FOCUS actually is.

FOCUS is an open specification for billing data, maintained by the FinOps Foundation under the Linux Foundation. It isn't a tool and it isn't a product. It defines a common set of column names and meanings, plus minimum requirements for anyone producing billing data, so that the same query works no matter whose bill it's running against.

It has been through several versions since 1.0 in late 2023, and the current published version on the FOCUS site is 1.4. The list of data generators is wider than the big three: AWS, Azure, Google Cloud and Oracle are there, but so are Snowflake, Databricks, MongoDB, Cloudflare, Vercel and others. For a SaaS company, that last part matters. Your bill isn't only cloud compute anymore, and FOCUS is slowly covering the rest of it.

The four cost columns worth knowing.

The spec is big, but most of the practical value sits in four columns that describe the same charge at different points in its life:

BilledCost is what appears on the invoice.

EffectiveCost is the cost after negotiated and commitment discounts, with prepaid commitments spread across their term. This is the one to use for trend reporting.

ListCost is what the charge would have cost at public list price.

ContractedCost is the cost at your negotiated rates, before commitment amortization.

If Issue #9 sounded familiar, it's because BilledCost and EffectiveCost are roughly the same split as the invoice view and the amortized view that finance and engineering end up arguing over. The mapping isn't exact, but the lesson is: agree on which column you're talking about before comparing any total.

Where it falls short.

Be realistic about the gaps. Coverage still differs by provider and by version, and Google Cloud has historically lagged AWS and Azure on native exports. Depending on which FOCUS version your provider exports, some detail, such as container-level split cost data on AWS, may only exist in the native report, which is why some teams end up exporting both.

And FOCUS standardizes data. It doesn't find waste, forecast spend, or tell you what to turn off. It makes your data comparable. What you do with it is still your job.

When it's worth your time.

If you run on a single cloud and the native cost tools already answer your questions, FOCUS is not an emergency. Skip it for now.

It starts paying off when you have more than one source of billing data: two clouds, or one cloud plus a handful of vendors that bill on usage. It also pays off if you expect to change cost tooling at some point, because a standard schema means less is tied to one vendor's export format.

The cheapest first step is small. If your provider offers a FOCUS export, turn it on and land the files in object storage. AWS Data Exports and Azure Cost Management exports both offer it. Then run one query: BilledCost against EffectiveCost for last month, grouped by service. That one comparison usually shows how much of your bill is being shaped by commitments and discounts, which is a more useful thing to know than most dashboards will tell you.

The actual takeaway: FOCUS doesn't make your bill smaller. It makes your bills comparable, which is the thing that has to be true before multi-cloud cost reporting can stop being a custom project. If you have one data source, wait. If you have several, start with a single export and a single query.

Running more than one cloud or billing source and fighting the data? Hit reply and tell me where the mapping breaks. I read every one.