Reserved capacity
For provisioned capacity tables that use the Standard table class, DynamoDB offers the ability to purchase reserved capacity for your read and write capacity. A reserved capacity purchase is an agreement to pay for a minimum amount of provisioned throughput capacity, for the duration of the term of the agreement, in exchange for discounted pricing.
Note
You can't purchase reserved capacity for replicated write capacity units (rWCUs). Reserved capacity is applied only to the Region in which it was purchased. Reserved capacity is also not available for tables using the DynamoDB Standard-IA table class or on-demand capacity mode.
Reserved capacity is purchased in allocations of 100 WCUs or 100 RCUs. The smallest reserved capacity offering is 100 capacity units (reads or writes). DynamoDB reserved capacity is offered as either a one-year commitment or in select Regions as a three-year commitment. You can save up to 54% off standard rates for a one-year term and 77% off standard rates for a three-year term. For more information about how and when you should purchase, see Amazon DynamoDB Reserved Capacity
When you purchase DynamoDB reserved capacity, you pay a one-time partial upfront payment and receive a discounted hourly rate for the committed provisioned usage. You pay for the entire committed provisioned usage, regardless of actual usage, so your cost savings are closely tied to use. Any capacity that you provision in excess of the purchased reserved capacity is billed at standard provisioned capacity rates. By reserving your read and write capacity units ahead of time, you realize significant cost savings on your provisioned capacity costs.
You can't sell, cancel, or transfer reserved capacity to another Region or account.
Note
Reserved capacity isn't a capacity dedicated to your organization. It's a billing discount applied to the use of provisioned capacity for reads and/or writes on your account.
