Reads vs writes vs storage
On-demand write units cost 5x reads, so write-heavy tables dominate the bill.
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Cloud Cost
AWS DynamoDB Cost Calculator
Estimate your DynamoDB bill. Enter monthly write and read requests and stored data, and see read, write and storage costs with the free storage tier applied.
Estimated monthly cost
$0
Write cost—
Read cost—
Storage cost—
First 25 GB free—
Annual estimate—
What the AWS DynamoDB Cost Calculator does
DynamoDB is a managed NoSQL database, and in on-demand mode you pay per request with no capacity to provision. The catch that shapes every DynamoDB bill is that writes cost about five times more than reads, roughly $1.25 per million write request units versus $0.25 per million reads. Storage adds $0.25 per GB after the first 25 GB free.
This DynamoDB cost calculator prices your monthly writes, reads and storage separately so you can see which dominates. Write heavy workloads like logging or event capture are usually write bound, while read heavy apps benefit from caching to keep read units down.
Heads up on pricing. The rates built into this tool are public list estimates for July 2026 and can change without notice. Providers also offer batch discounts, prompt caching and volume tiers that lower real costs, so treat the output as a planning estimate, not a quote.
The formula
write cost = writes ÷ 1,000,000 × $1.25
read cost = reads ÷ 1,000,000 × $0.25
storage = max(GB − 25, 0) × $0.25
read cost = reads ÷ 1,000,000 × $0.25
storage = max(GB − 25, 0) × $0.25
Worked example
For 10,000,000 writes, 50,000,000 reads and 25 GB stored: writes cost 10 × $1.25 = $12.50, reads 50 × $0.25 = $12.50, and storage is free within the first 25 GB, for about $25 a month.
Ways to lower your cloud costs
- Right size resources. Pick the smallest instance, memory or capacity that still meets your performance target.
- Commit to steady load. Reserved instances, savings plans and committed use discounts cut rates sharply for predictable workloads.
- Use serverless for spiky traffic. Scale-to-zero services mean you pay nothing while there are no requests.
- Tier cold storage. Move rarely accessed data to cheaper classes such as Glacier, Coldline or Archive.
- Cut data transfer. A CDN and keeping traffic within a single region reduce the egress charges that quietly grow with scale.
Frequently asked questions
How much does DynamoDB cost?
On demand, about $1.25 per million writes and $0.25 per million reads, plus $0.25 per GB storage after 25 GB free. Enter your usage above for a total.
Why are writes so much more than reads?
Writes must be durably replicated across availability zones, which costs more than serving a read. Budget accordingly for write heavy workloads.
Is on-demand or provisioned cheaper?
On demand suits spiky or unpredictable traffic with no idle cost. Provisioned capacity with auto scaling is cheaper for steady, high volume workloads.
How do I cut DynamoDB costs?
Cache hot reads with DAX or an application cache, batch writes, design keys to avoid hot partitions, and archive old data to S3.
Are these rates current?
They are July 2026 on-demand estimates. Confirm current pricing and regional rates on the AWS pricing page.