Event Hubs pricing

An ingress event is a unit of data 64 KB or less. Each one is a billable event. Larger messages are billed in multiples of 64 KB. For example, 8 KB is billed as one event, but a 96 KB message is billed as two events.

Events consumed from an event hub, as well as management operations and "control calls" such as checkpoints, are not counted as billable ingress events, but accrue to the throughput unit allowance.

Throughput units are explicitly selected by the customer, either through the Azure portal or Event Hub management APIs. Throughput units apply to all event hubs in a namespace, and each throughput unit entitles the namespace to the following capabilities:

1. Up to 1 MB per second of ingress events (= events send into an event hub), but no more than 1,000 ingress events, management operations, or control API calls per second.
2. Up to 2 MB per second of egress events (= events consumed from an event hub).
3. Up to 84 GB of event storage (sufficient for the default 24-hour retention period).

Throughput units are billed hourly, based on the maximum number of units selected during this hour.

If the total ingress throughput or the total ingress event rate across all event hubs in a namespace exceeds the aggregate throughput unit allowances, senders will get throttled and receive errors indicating that the ingress quota has been exceeded.

If the total egress throughput or the total event egress rate across all event hubs in a namespace exceeds the aggregate throughput unit allowances, receivers will get throttled and receive errors indicating that the egress quota has been exceeded. Ingress and egress quotas are enforced separately so that no sender can cause event consumption to slow down, nor a receiver can prevent events from being sent into Event Hub.

Note that the throughput unit selection is independent of the number of Event Hub partitions (sometimes referred to as shards in similar systems). There is no fixed charge for the partitions themselves. The charge is for the aggregate throughput units on all event hubs in a namespace. With this, customers can create enough partitions to support the anticipated maximum load for their systems, without incurring any throughput unit charges until the event load on the system actually requires higher throughput numbers, and without having to change the structure and architecture of their systems as the load on the system increases.

Example—Suppose you chose eight throughput units on a namespace, and create a single event hub with 32 partitions. If all partitions in this event hub see even load, each partition gets approximately 0.25 MB/s ingress throughput for a total aggregate throughput of 8 MB/s. If a single partition sees a usage spike to 1 MB/s, while eight other partitions only see half their peak load (0.125 MB/s), no throttling will occur.

Yes. Basic and Standard-tier namespaces can have a maximum of 20 throughput units (TUs) through the self-serve experience. You can request for up to 40 TUs for standard-tier namespaces by filing a support ticket. Please note that the immediate availability of additional capacity above 20 TUs per Azure subscription is not guaranteed. We recommend that customers anticipating a need for more than 20 TUs of Event Hubs capacity contact us to discuss requirements as early as possible in the planning cycle. If you require more than 40 TUs, we recommend that you consider using Dedicated Event Hubs.

If the size of the total amount of stored events exceeds the storage allowance for the selected number of throughput units (84 GB per TU for Standard tier, 10 TB per CU for Dedicated tier), the size that exceeds the allowance is charged at the regional rate listed in the pricing table. Event Hubs events are retained for a maximum of 7 days in the Standard tier, and 90 days in the Dedicated tier.

The total size of all stored events, including any internal overhead for event headers or on disk storage structures in all event hubs in a namespace is measured throughput the day. At the end of the day, the peak storage size is calculated. If the total size exceeds the storage allowance, the excess storage is billed using the locally redundant Azure blob storage rate.

There are no connection charges for sending events using HTTPs, regardless of the number of sending systems or devices. AMQP connections are metered, but the first 100 concurrent connections are free for every basic Event Hubs namespace, and the first 1,000 concurrent connections per subscription are free for standard Event Hubs. These allowances cover most receive scenarios and many service-to-service scenarios. Brokered connections charges usually only become significant if you plan to use AMQP on a large number of clients, for example to achieve more efficient event streaming. Brokered connections are charged at the rates listed on the Service Bus Connections pricing page.

There is no separate Brokered connection charge for Dedicated Event Hubs.

Event Hubs capture is enabled when any event hub in the namespace has the capture feature enabled. Capture is billed hourly per purchased throughput unit. As the throughput unit count is increased or decreased, Event Hubs capture billing will reflect these changes in whole hour increments.

Event Hubs capture does not impact egress rates for Event Hubs throughput units. You can still read at the full throughput unit rate of 2,000 events per second/2 MBps per throughput unit.

Event Hubs capture uses a storage account you provide on a schedule you provide. Because this is your storage account, any usage charges for this storage account will be billed to your Azure subscription. The shorter your capture window the more frequent storage transactions will occur.