Spanner committed use discounts provide deeply discounted prices in exchange for your commitment to continuously use Spanner compute capacity (as measured in nodes or processing units) for a one or three year period. One-year commitment provides a 20% discount whereas a three-year commitment provides a 40% discount! Spanner committed use discounts are available now and are applicable for all Spanner instance configurations in all regions.

Greater flexibility drives higher utilization

Spanner committed use discounts provide full flexibility in terms of how discounts are applied. Once you make a commitment to spend a certain amount on an hourly basis on Spanner from a billing account, you can get discounts on instances in different instance configurations, regions, and projects associated with that billing account. Both regional and multi-region instances can utilize the same spend commitment. This flexibility helps you achieve a high utilization rate of your commitment across regions and projects without manual intervention, saving you time and money. If for business reasons you need to migrate your application from single region to multi-region in future, you can do so with the same commitment while continuing to enjoy the discounts.

Committed use discounts along with other launches such as PostgreSQL interface and granular instance sizing democratize access to Spanner and make it easier for you to power more of your workloads with Spanner.

How to purchase committed use discounts

You can purchase a Cloud Spanner committed use discount in the Google Cloud Console billing page by selecting the Commitments tab and then selecting PURCHASE at the top as shown below. Read the purchasing spend-based commitments section in Google Cloud’s documentation for more details.

Once you click on PURCHASE, choose the billing account, commitment period and hourly commitment amount, in terms of equivalent on-demand spend.This amount represents the equivalent of on-demand costs that you would have incurred without the committed use discount.

After you purchase a Spanner committed use discount, it automatically applies to aggregated spending on compute capacity (as measured in nodes or processing units) in all regions, instance configurations, and projects. We have provided this flexibility so that you need not make separate commitments for each region and instead have higher savings by automatically applying the discount in all regions.

Spanner committed use discounts don’t apply to storage, backup, and network pricing. When you purchase a Spanner committed use discount, you pay the same commitment fee for the entire commitment period. You still receive the same discount percentage on applicable usage in the event of a price change. The commitment fee is billed monthly.

When is committed use discounts right for you?

Spanner committed use discounts are ideal when your spending on Spanner compute capacity has a predictable portion that you can commit to for a one or three year period. Let’s take an example.

Let’s say you have a couple of Spanner instances in different regions and you have provisioned a total of 125 nodes. Let’s say you are consistently spending an average of $100/hour on this computer capacity. Let’s further assert that you feel confident this usage rate will not decline over the next year.

This sort of steady usage represents an excellent opportunity to buy a Spanner committed use discount—in this case, a one-year commitment to spend $100/hour on Spanner nodes, in exchange for a 20% discount to that commitment. Let’s look at how such a purchase would apply to three different per-hour billing scenarios.

In the first hour, you spend $100 on Spanner nodes. This matches your commitment exactly, with no overage. With the commitment’s 20 percent discount applied, this hour would cost you $80, saving you $20.

Let’s say you scaled up Spanner nodes in the next hour, spending $110. You still enjoy a 20% discount for the $100 that your commitment covers. The remaining $10 gets billed at an on-demand rate.  Your bill for this hour would come to $80 plus the $10 of usage beyond the coverage of the commitment, for $90. Compared to the full $110 for the second hour, that still nets a $20 savings, just as in the previous hour.

In the third hour, you scale down Spanner nodes, spending only $85. Your bill for this hour would still be $80 based on a $100/hour commitment with the 20% discount applied.

As you can see, this commitment has saved you $45 over a three-hour span—even though one of those hours had a spending below the $100/hour commitment. Given that a typical month contains around 730 hours, a well-chosen committed use discount can add up to significant monthly savings for you. Let us see how.

For example, considering $100 per hour On-demand spend on Spanner:
Monthly expenditure based on On-demand rate = $100 per hour * 730 hours = $73,000
Monthly expenditure based on 1 year commitment =  ($100 per hour * (1-20%)) * 730 hours  = $58,400 per month
Total savings per month = $73,000 – $58,400 = $14,600
Total savings in 1 year = $14,600 per month * 12 months =  $175,200

You can save even more by making a 3 year commitment:
Monthly spend based on 3 year commitment =  ($100 per hour * (1-40%)) * 730 hours  = $43,800 per month
Total savings per month = $73,000 – $43,800 = $29,200
Total savings in 3 years = $29,200 per month * 36 months =  $1,051,200

These examples show how committed use discounts can help you achieve significant savings on Spanner usage. Now you can use committed use discounts to expand your Spanner usage to power more applications with Spanner’s consistency, availability and scalability guarantees.

Learn more

• Check out our documentation for more details on Spanner committed use discounts. For Spanner pricing information, take a look at our pricing page.
• To get started with Spanner, create an instance or try it out with a Spanner Qwiklab.