Atlas Flex clusters give you access to modern database features including MongoDB Search, MongoDB Vector Search, Atlas Stream Processing, triggers, and more. To learn more, see Cluster Types.
Flex clusters are capped at $30 per month. You pay a monthly base price, which includes:
5GB storage
100 operations/sec
unlimited data transfer
Flex clusters scale with your usage. If you use additional operations/sec, MongoDB charges you based on the following pricing tiers.
Usage Cost Summary
As a user of an Atlas Flex cluster, you pay between $8 and $30 for 30 days of usage. As for all Atlas clusters, the Flex cluster tier follows a pay-as-you-go model billed hourly.
The following table outlines the pricing for Flex clusters. Note that there is a volume discount as your usage increases.
Tier (ops/second) | Marginal Monthly Cost | Effective Discount | Total Monthly Cost | Total Hourly Cost |
|---|---|---|---|---|
0 - 100 (Base) | $8.00 | 0% | $8.00 | $0.0110 |
100 - 200 | $7.00 | 12.5% | $15.00 | $0.0205 |
200 - 300 | $6.00 | 25% | $21.00 | $0.0288 |
300 - 400 | $5.00 | 37.5% | $26.00 | $0.0356 |
400 - 500 | $4.00 | 50% | $30.00 | $0.0411 |
Estimate Your Monthly Cost
To estimate your monthly Flex cluster cost, find your cluster's current operations per second (ops/sec) usage. Then, compare that value against the tiers in the preceding table.
In Atlas, go to the Clusters page for your project.
If it's not already displayed, select the organization that contains your desired project from the Organizations menu in the navigation bar.
If it's not already displayed, select your desired project from the Projects menu in the navigation bar.
In the sidebar, click Clusters under the Database heading.
The Clusters page displays.
Find your Opcounters value.
Locate the Opcounters chart, which shows the operations per second that your cluster runs. To learn more about this and other available metrics, see Review Flex Cluster Metrics.
Compare the ops/sec value from the Opcounters chart against the tiers in the Usage Cost Summary table to estimate your marginal and total monthly cost. Your usage can vary throughout the month, so you might move between tiers as your workload changes, as the following examples show.
Examples
Scenario 1 - Monthly Usage
Your workload runs less than 100 ops/sec for 20 days, and then bursts up to 250 ops/second for 5 days. Then, for another 3 days, the workload bursts to 500 ops/second.
Usage | Cost |
|---|---|
Your workload runs less than 100 ops/sec for 20 days. | $0.011/hour * 24 hours * 20 days = $5.28 |
The workload bursts up to 250 ops/second for 5 days. | $0.0288/hour * 24 hours * 5 days = $3.46 |
The workload bursts to 500 ops/second for another 3 days. | $0.0411/hour * 24 hours * 3 days = $2.96 |
Total Usage Charge | $5.28 + $3.46 + $2.96 = $11.70 |
Scenario 2 - One Day Use
Your workload runs less than 100 ops/sec for 5 hours. It bursts up to 410 ops/second for 10 hours, followed by 9 hours at 150 ops/second. After these 24 hours, you delete the cluster.
Usage | Cost |
|---|---|
Your workload runs less than 100 ops/sec for 5 hours. | $0.011 hourly base cost * 5 hours = $0.055 |
The workload bursts up to 410 ops/second for 10 hours. | $0.0411/hour * 10 hours = $0.41 |
The workload drops to 150 ops/second for another 9 hours. | $0.0205/hour * 9 hours = $0.18 |
You delete the cluster. | (no charge) |
Total Usage Charge | $0.055 + $0.41 + $0.18 = $0.65 |
Scenario 3 - Migrating from a Retired M2 or M5 Tier
Important
As of February 2025, you can create Flex clusters, and can no longer create M2 and M5 clusters or Serverless instances in the Atlas UI, Atlas CLI, Atlas Administration API, Atlas Kubernetes Operator, HashiCorp Terraform, or Atlas CloudFormation Resources.
As of January 22, 2026, Atlas no longer supports M2 and M5 clusters and Serverless instances. All existing M2 and M5 clusters were migrated to Flex clusters.
Atlas migrated Serverless instances to Free clusters, Flex clusters, or Dedicated clusters according to your usage. To see which tiers Atlas migrated your instances to, consult the All Clusters page in the Atlas UI.
Suppose Atlas migrated your M2 or M5 cluster to a Flex cluster. Before the migration, this cluster billed at a flat monthly rate. Now, your cost depends on your workload's ops/sec usage instead of a fixed price.
Your workload runs less than 100 ops/sec for 25 days, and then bursts up to 200 ops/second for 5 days.
Usage | Cost |
|---|---|
Your workload runs less than 100 ops/sec for 25 days. | $0.011/hour * 24 hours * 25 days = $6.60 |
The workload bursts up to 200 ops/second for 5 days. | $0.0205/hour * 24 hours * 5 days = $2.46 |
Total Usage Charge | $6.60 + $2.46 = $9.06 |
To learn more about migrating your applications and tooling from a retired M2 or M5 cluster, see Migrate Programmatic Tools to Flex Clusters.
Flex versus M0 or Dedicated Clusters
Choose the cluster tier that matches your workload and budget.
Tier | Cost | Best For |
|---|---|---|
Free cluster ( | No cost | Learning MongoDB, prototyping, and other workloads that fit within the Atlas Free Cluster Limits. |
Flex cluster | $8 to $30 per month, based on usage | Development, testing, and low-traffic production workloads that need modern database features such as MongoDB Search, MongoDB Vector Search, and Atlas Stream Processing, without managing dedicated infrastructure. |
Dedicated cluster ( | Starts at $60 per month | Production workloads that need dedicated hardware, consistent resources, granular backup configuration, or features that Flex clusters don't support. |
To compare Flex cluster and Dedicated cluster feature support in detail, see Feature Support and Comparison. If your Flex cluster consistently reaches the throughput or storage limits described in the next section, consider switching to a Dedicated cluster for dedicated resources and higher limits.
Storage, Throughput, and Data Transfer Limits
Flex clusters have usage limits that are separate from the pricing tiers in this guide. To learn about all Flex cluster limits, see Atlas Flex Limitations.
Storage Over 5 GB
Flex clusters limit total data storage to 5 GB, which includes all uncompressed BSON documents stored in your collections plus their associated indexes. If your workload needs more storage, switch to a Dedicated cluster.
Throughput Above 500 Operations/Second
The pricing tiers in the Usage Cost Summary table apply only up to 500 operations/second. Above that point, Flex clusters enforce a separate hard limit rather than a higher pricing tier.
Atlas triggers a sub-second cooldown period on each connection before resuming that connection's operations. If the operation queue exceeds the operations per second limit, operations might wait in the queue for more than a second.
Data Transfer
Flex clusters include unlimited data transfer in the base price. Atlas doesn't charge Free clusters or Flex clusters for outgoing data transfer. To learn more, see Data Transfer Costs.