Atlas Limitations

Atlas limits how many of each kind of component you can create, and the number of connections allowed to a cluster based on cluster tier. These tables outline component and connection limits.


If any of these limits present a problem for your organization, please contact Atlas support.

Cluster Limits

Component Limit
Shards in Multi-Region Clusters 12
Shards in Single-region clusters 50
Total Nodes per Region of a Multi-Region Cluster 40
Electable Nodes per Region 7
Config Server Tier (minimum and maximum) M30

Connection Limits and Cluster Tier

Atlas sets the limits for concurrent incoming connections based on the cluster tier:

Cluster Tier Maximum Number of Concurrent Incoming Connections
M0 500
M2 500
M5 500
M10 1500
M20 3000
M30 3000
M40 / M40 Low CPU * 6000
M50 / M50 Low CPU * 16000
M60 / M60 Low CPU * 32000
M80 Low CPU * 64000
M140 96000
M200 / M200 Low CPU * 128000
M300 128000
M400 Low CPU * 128000

* Low CPU tiers are available with AWS clusters only.


Atlas reserves a small portion of connections to each Atlas cluster for supporting Atlas services. Contact Atlas support for more information on Atlas reserved connections.

Organization and Project Limits

Component Limit
Total Network Peering Connections per Atlas Project



Atlas limits the number of nodes per Network Peering connection based on the CIDR block and the region selected for the project.

Pending Network Peering Connections per Atlas Project 25
Database Users per Atlas Project 100
Atlas Users per Atlas Project 500
Atlas Users per Atlas Organization 500
API Keys per Atlas Organization 500
Access List Entries per Atlas Project 200
Users per Atlas Team 250
Teams per Atlas Project 100
Teams per Atlas Organization 250
Teams per Atlas User 100
Organizations per Atlas User 250
Clusters per Atlas Project 25
Projects per Atlas Organization 250
Custom MongoDB roles per Atlas Project 100
Assigned Roles per Database User 100
Hourly Billing per Atlas Project



A Technical Account Manager or Billing Admin can raise this limit.

Data Lake Tenants per Atlas User 25

Label Limits

Atlas also limits how long particular labels of components can be.

Component Character Length Limit
Cluster Name



Atlas truncates the cluster name to 23 characters in its internal interactions. In practice, this means:

  • Cluster names shorter than 23 characters can’t end with hyphen or dash (-)
  • Cluster names 23 characters or longer can’t use a hyphen or dash (-) as its 23rd character.
  • The first 23 characters in a cluster name must be unique within a project.
API Key Description 250