Missed Use of Committed Use Discounts for Compute Engine

For stable environments, such as production services or continuously running batch workloads, failing to apply CUDs results in materially higher compute spend without any operational benefit. The inefficiency is driven by pricing choice, not resource overuse.

Compute Engine instances are billed at on-demand rates by default, although some machine series (N1, N2, N2D, C2, M1, and M2) automatically receive sustained use discounts of up to 20% or 30% when they run for more than 25% of a billing month. Committed Use Discounts (CUDs) provide discounted pricing in exchange for a 1- or 3-year commitment to a consistent level of compute usage. Without CUDs, steady workloads incur higher on-demand costs.

There are two CUD models. Resource-based CUDs commit to a minimum amount of resources in a specific region and machine configuration. Compute flexible CUDs are spend-based: they commit to a minimum hourly spend and apply across projects, regions, and eligible machine families, as well as GKE and Cloud Run. Sustained use discounts do not apply to usage already covered by CUDs, so compare CUD savings against the SUD-adjusted rate.

• Review whether compute workloads run continuously or have stable baseline usage
• Assess whether current usage patterns indicate long-term commitment suitability
• Identify environments where compute demand is predictable across months

• Purchase appropriate Committed Use Discounts for workloads with steady usage
• Choose resource-based CUDs for stable machine types in a fixed region and project, and Compute flexible CUDs when usage shifts across regions, projects, or machine families
• Align commitment size and term length with expected baseline demand
• Periodically reassess commitments to ensure they still match workload patterns

• Committed use discounts (CUDs) for Compute Enginedocs.cloud.google.com
• Sustained use discountsdocs.cloud.google.com
• VM instance pricingcloud.google.com