AWS bills AgentCore short-term memory per gigabyte instead of per event

AWS bills AgentCore short-term memory per gigabyte instead of per event

12 October 2026: Amazon Web Services has changed how it charges for short-term memory in Amazon Bedrock AgentCore Memory, moving from a flat rate per event to billing on the data agents ingest, retrieve and store. Long-term memory pricing is unchanged. AWS says most workloads will cost less, and the change applies in every Region where AgentCore Memory is offered.

The new rates

Short-term memory is now charged on three meters, according to the announcement:

• Ingestion: $1.00 per GB
• Retrieval: $0.20 per GB
• Storage: $0.10 per GB-month

Ingestion and retrieval are billed per event, with a minimum billable size of 12 KB and a maximum of 64 KB for each event. Storage is billed on the actual size of each event. The AgentCore pricing page dates the new rates from 6 October 2026; until 5 October, short-term memory ingestion cost $0.25 per 1,000 new events.

Who pays less and who may not

AWS says most workloads will see lower costs, and that the largest reductions come in small-payload cases such as agents that write frequent, small events. The 12 KB minimum matters here: an event smaller than that is billed as if it were 12 KB, so a stream of tiny events is still charged at the floor, while a stream of events near the 64 KB ceiling is charged for the full size.

The flat per-event model charged the same whatever an event carried. Under the new model, cost follows volume, so agents that store long transcripts or large tool outputs in short-term memory are the ones to price again before assuming the change helps them. The old rate was $0.25 per 1,000 new events, so at the 12 KB floor 1,000 events now cost about $0.012 to ingest, while 1,000 events at the 64 KB ceiling cost about $0.064, before retrieval and storage.

Controlling the storage meter

The one lever AWS names directly is the time to live (TTL) on memory resources. A shorter TTL removes events sooner and so lowers the $0.10 per GB-month storage charge. Teams that set a generous TTL now have a reason to revisit it.

What to check on the next invoice

A team running agents on AgentCore can estimate the new bill from three numbers it already has: events per month, average event size, and how many of those events are read back. Ingestion and retrieval are the variable meters, and retrieval at $0.20 per GB is a fifth of the ingestion rate, so write-heavy agents are shaped differently from read-heavy ones.

The pricing page applies the new rates from 6 October 2026, so the October bill is the first to mix both models: usage up to 5 October at the per-event rate, and usage from 6 October by the gigabyte. Comparing the two halves of that report is the quickest way to see which way a given agent moved.

Sources

• AWS: Announcing consumption-based pricing for short-term memory in Amazon Bedrock AgentCore, 12 October 2026
• AWS: Amazon Bedrock AgentCore pricing (short-term memory rates as of 6 October 2026), read 13 October 2026