Azure · Free tool
Azure Cosmos DB cost calculator
Manual provisioned, Autoscale, and Serverless on the same workload. Region count and multi-region writes priced inline. The utilization tipping point where each pricing model wins is on the page, not in a spreadsheet.
Side-by-side: same workload, three pricing models
Manual provisioned
$0
peak RU/s × regions
Autoscale
$0
max RU/s × util
Serverless
$0
total RUs / mo
Cheapest model for this workload
Autoscale
$0/mo, $0/yr
Selected breakdown
If your Cosmos DB bill looks high, check these first
- Manual provisioned containers running below 50 percent utilization. Autoscale would be cheaper, with no application change.
- Multi-region writes enabled where only one region actually writes. Doubles the per-region rate for nothing.
- Free tier unused. 1000 RU/s + 25 GB permanently free, one per subscription. Apply it to the largest small container.
- Production replicated to four regions for redundancy. Two regions covers the failover case at half the cost.
- Continuous backup at 30 days on dev environments that reseed weekly. Switch to periodic, save $0.40/GB/month.
- Containers under 50 GB and under 5000 RU/s on Provisioned. Serverless is often cheaper on bursty access.
- Old indexing policy with all paths included. Custom indexing on hot fields cuts RU per write by 50 to 70 percent.
The three pricing knobs
Cosmos DB pricing has three knobs and one trap. The knobs: throughput model (Manual, Autoscale, or Serverless), region count, and multi-region writes. The trap is that the wrong model on a given workload can cost two to four times the right one, with no functional difference.
The RUs versus storage tradeoff post covers the autoscale tipping point math (around 65 percent steady utilization), the serverless break-even (around 50 million RUs per month), and the indexing audit that often cuts RU consumption in half before any pricing change.
Run this on your real account
Free 14-day audit, read-only Reader role, one-page CFO summary.
We pull every Cosmos account, identify Manual containers below 50 percent utilization, multi-region writes that should be single-write, unapplied free tier, and indexing policies that burn RUs on cold paths.
Frequently asked
Manual, Autoscale, or Serverless?
Manual is cheapest for steady workloads above 65 percent utilization. Autoscale is the right default for everything else: it bills at the highest RU/s consumed each hour, with a 10 percent floor. Serverless wins on workloads under 50 million RUs per month or with very bursty access patterns. The calculator above prices all three on the same numbers, so the right answer is on the page.
How does multi-region pricing actually work?
Each region you replicate to multiplies the throughput cost. A 4000 RU/s container replicated to three regions costs three times the single-region throughput. Multi-region writes doubles the per-region rate on top of that, so a 4000 RU/s container with multi-region writes across three regions costs six times the single-region single-write rate. Storage is also charged per region. Most teams enable multi-region for failover (single-write) where a single Azure region outage demands a manual failover trigger but no extra cost shape, then later add multi-region writes without re-checking the bill.
When does Serverless break?
Serverless caps at 5000 RU/s per container and 50 GB storage. Above that, you have to switch to Provisioned. The break-even between Serverless and Autoscale on a given workload is around 30 to 50 million RUs per month: below it, Serverless is cheaper, above it, Autoscale wins because the per-RU rate is lower at scale. Serverless also does not support multi-region replication, so any workload that needs replication is on Provisioned by default.
Should I use the free tier?
Yes, on every account that has not used it yet. The free tier gives 1000 RU/s and 25 GB storage permanently, per subscription, on one Cosmos account. That is roughly $58 per month off the bill. Most teams enable it on dev or staging by default and never apply it to production, where it would still cover the first 1000 RU/s. Apply it where it offsets the biggest container.
How much does continuous backup cost?
Periodic backup includes two copies free. Continuous backup at 7-day retention is around $0.20 per GB per month. Continuous backup at 30-day retention runs about $0.40 per GB per month. The premium buys point-in-time restore. On a 100 GB container, that is $20 to $40 per month. Worth it on production. Wasteful on dev environments that get reseeded weekly.
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