Cloud costs · DynamoDB
DynamoDB on-demand vs provisioned cost calculator.
On-demand bills per request; provisioned bills for the capacity you reserve, used or not. Enter your average and peak traffic to see which costs less and how busy provisioned capacity must be to win.
With 50 reads and 10 writes a second on average, peaking at 200 and 40, and 2 KB items read strongly consistent, on-demand costs $49.28 a month in US East and provisioned (sized to the peak) costs $56.94. Provisioned wins only when average use of the capacity is above about 28.9%.
Your numbers
Result
Method and limits
Units. One read request unit covers one strongly consistent read, or two eventually consistent reads, of an item up to 4 KB; larger items round up in 4 KB steps. One write request unit covers one write of an item up to 1 KB, rounding up in 1 KB steps. Provisioned capacity (RCU and WCU) uses the same units per second.
Prices (US East, N. Virginia, standard table class). On-demand: $0.125 per million read request units and $0.625 per million write request units. Provisioned: $0.00013 per RCU-hour and $0.00065 per WCU-hour. A month is 730 hours.
Method. On-demand cost = average units per second x seconds in the month x price. Provisioned cost = peak units per second (rounded up) x 730 x hourly price, i.e. capacity fixed at your peak with no auto scaling. A provisioned RCU-hour ($0.00013) covers 3,600 read request units, which cost 3,600 x $0.000000125 = $0.00045 on-demand, so fully used provisioned capacity costs 28.9% as much. Provisioned therefore only wins above roughly 28.9% average utilisation of the reserved capacity, and the same ratio holds for writes ($0.00065 against 3,600 x $0.000000625).
Not included. Auto scaling, reserved capacity, the provisioned free tier (25 RCU and 25 WCU), storage ($0.25 per GB-month after 25 GB, the same in both modes), global tables, indexes, streams, backups, transactional requests, the Standard-IA table class and other regions.
Price date. List prices in USD, on-demand and pay-as-you-go, retrieved 2026-10-16 and stored in this page. Providers change prices without notice, so confirm on the provider's pricing page before you commit spend. Nothing you type leaves your browser.
Sources
- AWS Price List, AmazonDynamoDB offer, US East (N. Virginia) (retrieved 2026-10-16): on-demand request unit prices, provisioned capacity prices and storage.
- DynamoDB Developer Guide: on-demand capacity mode (retrieved 2026-10-16): definition of a read request unit and a write request unit.
- DynamoDB Developer Guide: throughput capacity (retrieved 2026-10-16): provisioned mode charges for provisioned capacity, not consumed capacity.
FAQ
Is DynamoDB on-demand more expensive than provisioned?
Per request, yes: a unit of provisioned capacity costs about 28.9% of the on-demand price per unit if you use it fully. But provisioned capacity is billed whether used or not. In this example on-demand is $49.28 against $56.94, while for nearly flat traffic (100 reads and 20 writes a second, peak 110 and 22) on-demand is $65.70 and provisioned $20.88.
What is a read request unit?
One strongly consistent read of an item up to 4 KB, or two eventually consistent reads of such an item, according to the DynamoDB Developer Guide.
What is a write request unit?
One write of an item up to 1 KB. A 3 KB item costs 3 write request units.
When should I use provisioned capacity?
When traffic is steady and predictable so your average use of the reserved capacity stays above the break-even shown in the results. Spiky or unknown traffic is cheaper and safer on-demand.
Does this include storage?
No. Storage costs $0.25 per GB-month after the first 25 GB in both modes, so it does not change the comparison.