Committed use discounts cut Google Cloud rates in exchange for a one or three year commitment. Read where the lock in bites before you size the commitment off a peak month.
A committed use discount lowers the rate, but it only saves money if the committed baseline sits below your steady state usage rather than above it.
Google Cloud offers two committed use discount models. They lower the rate the same way but commit to different things, and the right one depends on how stable your machine mix is.
Google documents both models on the committed use discounts overview and the Compute Engine CUD documentation. Read the commitment unit carefully, because it sets how much flexibility you keep.
Google Cloud CUD models compared
| Attribute | Resource based | Spend based |
|---|---|---|
| Commits to | Resource quantity in a region | Hourly dollar spend on a service |
| Flexibility | Low, tied to machine type | Higher, flexes across types |
| Discount depth | Deepest | Moderate |
| Best fit | Stable, fixed workloads | Variable mix, steady baseline |
| Term options | One or three year | One or three year |
Size the commitment to your steady state floor, the level of usage that never drops below a line across a full year. Anything above that floor is better left on demand or covered by a smaller spend based commitment.
Google explains that sustained use discounts already apply automatically to some services, and the pricing principles sit on the Google Cloud pricing page. Account for those automatic discounts before you model the incremental CUD saving, or you will overstate the benefit.
Take the three year term only where the baseline is genuinely durable. Match the commitment term to the workload horizon, and never let the deeper headline discount pull you past the point where you are confident the usage persists.
CUDs are one lever in a larger negotiation. Many enterprises also hold a Google Cloud commitment contract with custom pricing, and the CUDs sit alongside it. Treat the two together.
Google describes spend based committed use discounts in more depth in its spend based CUD documentation. Use the figures there as the floor for what is publicly available, then negotiate the custom commitment on top.
The common advice is to maximize the three year commitment because it carries the deepest discount. We disagree. In roughly two thirds of the commitment reviews we ran in 2024 and 2025, the deeper term locked in capacity that the estate later could not use, and the idle commitment wiped out the rate saving. The buyer side move is to commit only to the durable steady state floor, take the longer term only where the baseline is certain, and cover everything above the floor with flexible spend based or on demand capacity. A smaller commitment you fully use beats a larger one you partly waste.
Source: Redress Compliance advisory engagement file, 2024 to 2025.
A committed use discount only saves money when the committed baseline sits below your steady state floor, never above it.
Overcommitment is avoided with a year of usage data and a disciplined floor. Commit to the floor, layer flexibility above it, and negotiate the custom contract separately.
Start with a one year commitment on the clear floor, observe the actual utilization, then extend or deepen only on proven baseline. Staging avoids the lock in that off the shelf advice walks estates into.
A committed use discount lowers your Google Cloud rate in exchange for a one or three year commitment to a level of usage or spend. The discount is real, but it only saves money when the committed baseline sits below your steady state usage rather than above it.
Resource based CUDs commit to a quantity of a resource, such as vCPU and memory in a region, and carry the deepest discount but the least flexibility. Spend based CUDs commit to an hourly dollar amount on a service and flex across machine types, usually at a smaller discount.
Take the three year term only where the baseline usage is genuinely durable, because it carries the deepest discount but the heaviest lock in. Match the term to the workload horizon, and never let the deeper headline rate pull you past the point where you are confident usage persists.
Size it to your steady state floor, the level of usage that never drops below a line across a full year of data. Commit at or below that floor, and cover everything above it with flexible spend based or on demand capacity to avoid paying for idle commitment.
Unused committed capacity is a sunk cost. You pay for the commitment whether or not you use it, so an oversized commitment can wipe out the rate saving entirely. In our reviews, peak sized commitments left 15 to 30 percent of committed capacity idle.
Sustained use discounts apply automatically to some services and should be netted out before you model the incremental CUD saving. Estates that ignore them double count the expected benefit and overstate the CUD payback.
Yes. Many enterprises hold a custom Google Cloud commitment contract that sits alongside the public CUDs. Treat the two together, using the public CUD figures as the floor and negotiating the custom commitment rate on top.
Stage the commitment. Start with a one year commitment on the clear steady state floor, observe actual utilization, then extend or deepen only on a proven baseline. Staging avoids the lock in that maximalist advice walks estates into.
The CUD comparison, the commitment sizing model, the overcommit traps, and the negotiation levers on the broader Google Cloud agreement.
Used across more than five hundred enterprise engagements. Independent. Buyer side. Built for procurement leaders running the next renewal cycle.
