DocumentDB Cost Calculator
Estimate an Amazon DocumentDB bill across instance hours, cluster storage, I/O requests and backup beyond the free allowance.
About DocumentDB Cost Calculator
DocumentDB uses the same decoupled architecture as Aurora: one shared cluster volume billed once no matter how many instances read it, plus a per-request I/O charge and instance-hours for each node. Backup storage up to the size of the cluster volume is free, so only the retention window and change rate that push you past that size cost anything. Every rate is an editable input with a realistic us-east-1 default — confirm current prices with AWS for your region. Because storage is shared, adding a replica to DocumentDB only adds instance-hours and read I/O — which makes the compute share of the bill the number that tells you whether to scale out or scale up.
Formula
DocumentDB Cost
monthly = instances × hourly × hours + GB × storage rate + I/O millions × I/O rate + max(0, backup GB − cluster GB) × backup rate.
- instances
- Writer and replicas, each billed at the full instance rate
- cluster storage
- Shared distributed volume, billed once for the whole cluster
- I/O request
- One page read or write against the cluster volume
- free backup
- Backup storage equal to the cluster volume size, at no charge
Worked example
With the default values below, DocumentDB Cost Calculator returns Estimated Monthly Cost of $714.78. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Instances in the clusteraccepts 1–16 instances
- 3 instances
- Instance priceminimum 0 $/hour
- 0.277 $/hour
- Billed hours per monthaccepts 0–744 hours
- 730 hours
- Cluster storage in useaccepts 0–65,536 GB
- 250 GB
- Storage priceminimum 0 $/GB-month
- 0.1 $/GB-month
- I/O requests per monthaccepts 0–500,000 millions
- 400 millions
- I/O priceminimum 0 $/million
- 0.2 $/million
- Backup storage heldaccepts 0–500,000 GB
- 400 GB
- Backup storage priceminimum 0 $/GB-month
- 0.021 $/GB-month
Results
- Estimated Monthly Cost
- $714.78
- Instance Hours
- $606.63
- Cluster Storage
- $25.00
- I/O Requests
- $80.00
- Backup Storage
- $3.15
- Compute Share of the Bill
- 84.9%
Step by step
- 1Values used
- 2DocumentDB Cost
- 3Estimated Monthly Cost= 714.78
- 4Instance Hours= 606.63
- 5Cluster Storage= 25.00
- 6I/O Requests= 80.00
- 7Backup Storage= 3.15
- 8Compute Share of the Bill= 84.9
Assumptions and limits
- The result is derived only from the 9 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is DocumentDB Cost calculated?
monthly = instances × hourly × hours + GB × storage rate + I/O millions × I/O rate + max(0, backup GB − cluster GB) × backup rate. DocumentDB uses the same decoupled architecture as Aurora: one shared cluster volume billed once no matter how many instances read it, plus a per-request I/O charge and instance-hours for each node. Backup storage up to the size of the cluster volume is free, so only the retention window and change rate that push you past that size cost anything. Every rate is an editable input with a realistic us-east-1 default — confirm current prices with AWS for your region.
Why does DocumentDB Cost matter?
Because storage is shared, adding a replica to DocumentDB only adds instance-hours and read I/O — which makes the compute share of the bill the number that tells you whether to scale out or scale up.
What values do I need to enter?
This calculator takes 9 inputs: Instances in the cluster, Instance price, Billed hours per month, Cluster storage in use, Storage price, I/O requests per month, I/O price, Backup storage held, Backup storage price. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.
Are these prices current?
They are realistic us-east-1 on-demand defaults and nothing more. DocumentDB rates vary by region and instance family, so confirm each one against the AWS DocumentDB pricing page for your region.