Azure Event Hubs quotas and limits

The following tables provide quotas and limits specific to Azure Event Hubs. For information about Event Hubs pricing, see Event Hubs pricing.

Common limits for all tiers

The following limits are common across all tiers.

Limit Notes Value
Size of an event hub name - 256 characters
Size of a consumer group name Kafka protocol doesn't require the creation of a consumer group.

Kafka: 256 characters

AMQP: 50 characters

Number of non-epoch receivers per consumer group - 5
Number of authorization rules per namespace Subsequent requests for authorization rule creation are rejected. 12
Number of calls to the GetRuntimeInformation method - 50 per second
Number of virtual networks (VNet) - 128
Number of IP Config rules - 128
Maximum length of a schema group name 50
Maximum length of a schema name 100
Size in bytes per schema 1 MB
Number of properties per schema group 1024
Size in bytes per schema group property key 256
Size in bytes per schema group property value 1024

Basic vs. standard vs. premium vs. dedicated tiers

The following table shows limits that may be different for basic, standard, premium, and dedicated tiers.


  • In the table, CU is capacity unit, PU is processing unit, and TU is throughput unit.
  • You can configure TUs for a basic or standard tier namespace or PUs for a premium tier namespace.
  • When you create a dedicated cluster, 1 CU is assigned to the cluster. If you enable the Support Scaling option while creating the cluster, you'll be able to scale out by increasing CUs or scale in by decreasing CUs for the cluster yourself. For step-by-step instructions, see Scale dedicated cluster. For clusters that don't support the Support Scaling feature, submit a ticket To adjust CUs for the cluster.
Limit Basic Standard Premium Dedicated
Maximum size of Event Hubs publication 256 KB 1 MB 1 MB 1 MB
Number of Event Hub consumer groups per event hub 1 20 100 1000
No limit per CU
Number of Kafka consumer groups per Namespace NA 1000 1000 1000
Number of brokered connections per namespace 100 5,000 10000 per PU

For example, if the namespace is assigned 3 PUs, the limit is 30000.
100, 000 per CU
Maximum retention period of event data 1 day 7 days 90 days 90 days
Maximum TUs or PUs or CUs 40 TUs 40 TUs 16 PUs 20 CUs
Number of partitions per event hub 32 32 100 per event hub, but there's a limit of 200 per PU at the namespace level.

For example, if a namespace is assigned 2 PUs, the limit for total number of partitions in all event hubs in the namespace is 2 * 200 = 400.
1024 per event hub
2000 per CU
Number of namespaces per subscription 1000 1000 1000 1000 (50 per CU)
Number of event hubs per namespace 10 10 100 per PU 1000
Capture N/A Pay per hour Included Included
Size of compacted event hub N/A 1 GB per partition 250 GB per partition 250 GB per partition
Size of the schema registry (namespace) in mega bytes N/A 25 100 1024
Number of schema groups in a schema registry or namespace N/A 1 - excluding the default group 100
1 MB per schema
1 MB per schema
Number of schema versions across all schema groups N/A 25 1000 10000
Throughput per unit Ingress - 1 MB/s or 1000 events per second
Egress – 2 MB/s or 4096 events per second
Ingress - 1 MB/s or 1000 events per second
Egress – 2 MB/s or 4096 events per second
No limits per PU * No limits per CU *

* Depends on various factors such as resource allocation, number of partitions, storage, and so on.


You can publish events individually or batched. The publication limit (according to SKU) applies regardless of whether it is a single event or a batch. Publishing events larger than the maximum threshold will be rejected.

The following table shows the list of features that are available (or not available) in a specific tier of Azure Event Hubs.

Feature Basic Standard Premium Dedicated
Tenancy Multi-tenant Multi-tenant Multi-tenant with resource isolation Exclusive single tenant
Private link N/A Yes Yes Yes
Customer-managed key
(Bring your own key)
N/A N/A Yes Yes
Capture N/A Priced separately Included Included
Dynamic Partition scale out N/A N/A Yes Yes
Ingress events Pay per million events Pay per million events Included Included
Runtime audit logs N/A N/A Yes Yes


Included in the table means the feature is available and there's no separate charge for using it.

Next steps

You can learn more about Event Hubs by visiting the following links: