Billing fundamentals

The AWS bill is assembled from the Cost and Usage Report: millions of line items, each carrying a usage type, an operation, several different rate columns, and a web of credits, discounts, and allocations layered on top. Cost Explorer summarizes it well, but the summary hides exactly the mechanics you need when a number surprises you.

Unblended, blended, amortized, and net rates answer different questions, and using the wrong one quietly breaks showback, forecasting, and savings math. Cost allocation tags decide whether spend can be attributed at all. This is unglamorous foundation work, and every other optimization depends on it.

These articles explain the bill's actual mechanics: what each rate type means, how the CUR is structured, and how to build cost visibility that survives contact with finance.