EventBridge event streams support two billing methods: by event volume and by CU (Capacity Unit) quota. You select a billing method when you create an event stream.
Billing by event volume
Billable item | Unit price |
Event volume | USD 0.41 per million events |
Idle resource fee | 0.14 USD/day |
How event volume is calculated
Event volume is the total number of events that an event stream pulls from the input data source. Each 64 KB of event data counts as one event.
Formula: Event volume = CEILING(Size of a single event / 64 KB)
For example, a 256 KB event is billed as 4 events (256 / 64 = 4). A 300 KB event is billed as 5 events (CEILING(300 / 64) = 5).
Retries also count toward event volume. Each retry is billed as one event based on the configured retry rule.
Idle resource fee
If an event stream receives no inbound data for one month, an idle resource fee of USD 0.14/day is charged. This fee stops when data starts flowing into the event stream or when you delete the event stream.
Billing by CU quota
A CU (Capacity Unit) is the unit of capacity for an EventBridge task. Each CU provides:
Up to 5,000 Events Per Second (EPS). Actual performance depends on upstream and downstream services.
Up to 50 MB/s peak throughput.
| Billable item | Unit price |
|---|---|
| CU quota | 0.034 USD/hour/CU |
Allocate a minimum of 1 CU per task. To handle variable workloads, specify minimum and maximum CU values for auto scaling when you create the task.
Pricing examples
Example 1: Low-volume, event-based billing
An event stream processes 2 million events per month. Each event is under 64 KB.
| Item | Calculation | Cost |
|---|---|---|
| Event volume | 2,000,000 events x USD 0.41/1,000,000 | USD 0.82 |
| Monthly total | USD 0.82 |
Example 2: Large events with chunking
An event stream processes 1 million events per month. Each event is 200 KB.
Each 200 KB event counts as CEILING(200 / 64) = 4 events. Billed event volume = 1,000,000 x 4 = 4,000,000 events.
| Item | Calculation | Cost |
|---|---|---|
| Event volume | 4,000,000 events x USD 0.41/1,000,000 | USD 1.64 |
| Monthly total | USD 1.64 |
Example 3: CU-based billing
An event stream runs continuously with 2 CUs allocated for one month (730 hours).
| Item | Calculation | Cost |
|---|---|---|
| CU quota | 2 CUs x 730 hours x USD 0.034/hour/CU | USD 49.64 |
| Monthly total | USD 49.64 |