Cost allocation and showback

Attribute spend to cost centres by tag, prorate shared costs fairly, and keep the unallocated remainder visible instead of buried.

Allocation turns a cloud bill into an accountable ledger: who caused this spend, and what should they see on their showback report.

Configuring allocation #

An administrator sets this up under Integrations:

Cost-centre tag keys, in priority order. Flux reads the first one a resource carries, so you can migrate tagging conventions without a big-bang retag — list the new key first and the old one as fallback.

cost-center, department, team

Shared values (optional). Cost centres whose spend is genuinely shared infrastructure rather than one team’s consumption.

shared, platform

Matching is case-insensitive, so Cost-Center and cost-center behave the same.

How shared costs are prorated #

Spend landing in a shared cost centre is distributed across the others in proportion to their direct spend.

A worked example:

Cost centre Direct Shared allocation Total
Brands $60,000 $6,000 $66,000
Supply $30,000 $3,000 $33,000
Shared pool $9,000 (distributed) —

Brands consumed twice what Supply did, so it absorbs twice the shared cost.

Proportional, not equal Splitting shared cost evenly across teams penalises small consumers and subsidises large ones. Proportional attribution is the defensible default, and it is what Flux does.

Unallocated spend #

Spend on resources carrying none of the configured tags is reported as unallocated — never silently absorbed into another centre or dropped from the total.

Allocation coverage is reported as a headline percentage. This is the number to drive: 94% allocated means 6% of your bill has no owner.

Coverage is the work The gap is not a reporting problem to hide, it is a tagging problem to fix. Which is what the next section is for.

Tag hygiene #

The tag hygiene report exists to close that gap. It shows:

  • Tag coverage — what proportion of resources carry any tags
  • Tagged spend — what proportion of cost is on tagged resources, which matters far more than resource count
  • Unallocatable spend — the dollar figure sitting on untagged resources
  • Required-tag compliance — against your organization’s mandated tags
  • Per subscription, ordered by untagged spend
  • The costliest untagged resources, ranked

That last list is the practical one. Tagging the top ten resources by cost typically moves coverage further than tagging a hundred small ones.

Platform resource types that legitimately carry no tags can be excluded from compliance percentages so they do not permanently depress the number.

Showback #

Once configured, the allocation report gives each cost centre its direct spend, its share of prorated shared cost, its total, and its percentage of the estate.

Export it and send it out. Every figure traces back to the same governed snapshot the dashboards use, so a challenged number can be reconciled rather than argued about.

Unit economics #

The same tagging mechanism drives unit economics — spend per business dimension such as brand, plant, product, or customer. See Budgets and unit economics.