LearnGlossary

Blended vs unblended cost: meaning and cost impact

Updated 26 October 2026 · Published by Zoorik

Blended vs unblended cost compares two ways AWS shows the same usage cost across an organization’s accounts. Unblended cost shows each account its own charges. Blended cost gives every account one average rate per usage type.

What is unblended cost?

Unblended cost keeps each line item’s own rate. EC2 and RDS hours that a Reserved Instance (RI) covers show $0. It’s the default in AWS Cost Explorer and AWS Budgets.

  • Blended cost: its average rate mixes on-demand, RI and Savings Plans usage.
  • Net unblended cost: the actual cost after discounts. Its report column appears only in months with a discount.
  • Amortized cost: Savings Plans and reservation fees spread evenly across the month.

An example from AWS

The AWS Billing User Guide has two accounts on t2.small in a 720-hour month. Three RIs cover all 2,160 hours of account 1. Account 2 runs 720 on-demand hours at $0.023 an hour.

  • Unblended: account 1 shows $0.00, account 2 $16.56.
  • Blended: $16.56 over 2,880 hours gives $0.00575 an hour. Account 1 shows $12.42, account 2 $4.14.

Both views total $16.56. The RI fees are separate line items, outside both.

Both views total $16.56, but blended cost shows $12.42 of it on account 1 AWS Billing User Guide example: two accounts on t2.small, 720-hour month. Two bars on one shared dollar scale, with ticks from $0 to $16. The Unblended bar, each account's own rate, is one amber segment labelled Account 2, 720 on-demand hours, $16.56, and under it, at $0, a label reads Account 1, 2,160 RI hours, $0.00. The Blended bar, one rate of $0.00575 an hour for all 2,880 hours, splits into Account 1, $12.42, and Account 2, $4.14. One line at the end of both bars reads Total $16.56. Both views total $16.56, but blended cost shows $12.42 of it on account 1 AWS Billing User Guide example: two accounts on t2.small, 720-hour monthUnblendedeach account's own rateAccount 2, 720 on-demand hours$16.56Account 1, 2,160 RI hours$0.00Blendedone rate, $0.00575 an hour, for all 2,880 hoursAccount 1$12.42Account 2$4.14Total $16.56$0$4$8$12$16
AWS’s own example: the same $16.56 of usage cost in both views, where blending spreads it by hours, and the RI fees, separate line items, are not shown.

Why it matters for your cloud cost

  • Blended vs unblended cost in AWS doesn’t change what you pay, only which account each cost shows on.
  • Blended cost hides which account got the RI discount. On-demand account 2 shows only $4.14.
  • AWS’s Cloud Financial Management blog says most customers need only unblended cost.
  • To reduce your cloud cost, see what moves it.
  • The free assessment works out what your clusters and disks could save.

Read next: How to reduce cloud costs

Sources: AWS, “Understanding your AWS Cost Datasets: A Cheat Sheet” (opens in a new tab) (AWS Cloud Financial Management blog); AWS, “Line item details” (opens in a new tab) (AWS Cost and Usage Reports User Guide); AWS, “Understanding Consolidated Bills” (opens in a new tab) (AWS Billing User Guide).

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