The "Export as CSV" button. Take the estimate to your finance team before you launch the cluster. A 10-minute conversation with the calculator saves a $2,000 surprise on your next AWS bill.
AWS DocumentDB is not cheap, but it is predictable. The pricing calculator is your only defense against I/O shock. Use the replicas slider carefully, respect the I/O rate, and always— always —model the reserved instance discount.
The calculator assumes you are constantly at that number. If you bulk load 2TB of data for one day then delete it, the calculator won't catch that nuance—you must manually adjust. The true power of the AWS DocumentDB calculator is scenario modeling. Scenario A: The Serverless Gamble AWS DocumentDB recently added Serverless (v4.0). Instead of picking r5.large , you pick "Serverless" and define a capacity range (0.5 to 16 ACUs—Application Capacity Units). aws documentdb pricing calculator
"I need to retain 30 days of change logs." Enter 2,000GB. The calculator adds that cost. Most users forget this, then cry when the bill arrives. Common Pitfalls (And How the Calculator Saves You) | Pitfall | Calculator Fix | | :--- | :--- | | Forgetting Data Transfer | The calculator has a "Data Transfer" tab. If you query DocumentDB from EC2 in different AZs, you pay cross-AZ fees. Add those here. | | Assuming 100% Utilization | The calculator defaults to "Always On" (730 hours/month). For dev environments that shut down at night, use the "Partial month" toggle. | | Mixing Instance Families | Your primary can be r5.large but your read replica can be r5.xlarge . The calculator allows asymmetric clusters. Use it. | Final Verdict: Is the Calculator Good Enough? Yes, but only if you have metrics.
If you are guessing your I/O rate ("Uh, maybe 500 IOPS?"), the calculator is worthless—garbage in, garbage out. However, if you export CloudWatch metrics from a staging environment (e.g., DatabaseCursors , ReadIOPS , WriteIOPS ), the calculator becomes a crystal ball. The "Export as CSV" button
If you are migrating from open-source MongoDB to AWS DocumentDB (a purpose-built database for JSON data), you quickly realize one truth: Performance is elastic, but costs can be rigid. Unlike Amazon S3, where pricing is simple storage arithmetic, DocumentDB pricing is a multi-dimensional chess game involving instances, IOPS, storage, and backups.
Use the "Detailed I/O mode." It lets you separate storageReadIOs (query results) from storageWriteIOs (index updates and document mutations). 4. The Storage Gap DocumentDB storage auto-scales up to 64TB. You tell the calculator your average used storage (e.g., 500GB). But here is the nuance: You pay for the high-water mark, not the average. AWS DocumentDB is not cheap, but it is predictable
MongoDB compatibility. Serverless scalability. Enterprise price tags.