Cosmos DB
Azure Cosmos DB — commitment brief
Data sourced: March 2026. Verify current figures at the Azure Pricing Calculator.
Coverage summary
Azure Cosmos DB supports reserved capacity in RU/s (Request Units per second) increments, applicable across all Cosmos DB APIs — NoSQL, MongoDB, Cassandra, Gremlin, and Table. Discounts scale with reservation size: small reservations (100 RU/s units) save 20–30%, while large-scale commitments (30M+ multi-master RU/s) can reach up to ~63% off pay-as-you-go. Serverless accounts are not eligible for reservations. Cosmos DB is also covered by the Azure Database Savings Plan (1-yr only) as a flexible alternative.
What is covered: Provisioned throughput costs (RU/s), across both single-region write and multi-region write (multi-master) configurations. Reservation discount applies automatically across all Cosmos DB databases and containers in the reservation scope.
What is not covered: Storage (billed per GB), networking/egress, Serverless accounts, throughput consumed above the reserved amount (billed at pay-as-you-go). Autoscale accounts use a 1.5x RU/s multiplier — a 100,000 RU/s reservation covers approximately 66,667 RU/s of autoscale capacity.
Azure Hybrid Benefit
Not applicable. Cosmos DB is a fully managed PaaS database with no underlying OS or SQL Server license. AHB is not available for this service.
SKU / tier coverage
100 RU/s — Single-region write
✅ Yes
✅ Yes (DB SP)
20%
30%
Base unit; up to 999,900 RU/s in 100-unit increments
100 RU/s — Multi-master
✅ Yes
✅ Yes (DB SP)
20%
30%
Multi-region write configuration
1,000,000 RU/s — Single-region
✅ Yes
✅ Yes (DB SP)
27%
~40%
Progressive discount tier
1,000,000 RU/s — Multi-master
✅ Yes
✅ Yes (DB SP)
32%
~45%
5,000,000 RU/s — Single-region
✅ Yes
✅ Yes (DB SP)
~35%
~50%
5,000,000 RU/s — Multi-master
✅ Yes
✅ Yes (DB SP)
~40%
~55%
10,000,000 RU/s — Single-region
✅ Yes
✅ Yes (DB SP)
~40%
~55%
10,000,000 RU/s — Multi-master
✅ Yes
✅ Yes (DB SP)
~45%
~60%
30,000,000 RU/s — Multi-master
✅ Yes
✅ Yes (DB SP)
~48%
~63%
Maximum discount tier
Serverless accounts
❌ No
✅ Yes (DB SP)
—
—
Not eligible for RU/s reservations; Database Savings Plan applies
Reservation vs. Azure Database Savings Plan
Reservation: Scoped to a specific RU/s quantity and write configuration (single vs. multi-master). Delivers the highest discount, scaling up to ~63% at 3-yr for large multi-master deployments. Discount applies automatically across all Cosmos DB APIs in scope — no per-API selection needed. Best for stable, provisioned-throughput workloads with predictable RU/s usage.
Azure Database Savings Plan (1-yr only): Hourly spend commitment covering Cosmos DB, Azure SQL Database, Azure SQL Managed Instance, Azure Database for PostgreSQL, and other eligible managed databases. Flexible — applies across regions and database engines automatically. Covers Serverless accounts (unlike reservations). Up to ~35% savings vs. pay-as-you-go. Best for mixed database estates or Serverless workloads.
Regional availability
Azure Cosmos DB reserved capacity can be applied across all Azure regions. When you purchase a Cosmos DB reservation, it functions as a monetary credit that covers provisioned throughput costs across all regions where your Cosmos DB resources run — discounts apply automatically in each region at the ratio equivalent to that region's on-demand pricing. You do not need a separate reservation per region.
Notable exclusions: Azure Government and Azure China regions are not supported for Cosmos DB reservations. Serverless accounts are not eligible for RU/s reservations in any region (use the Azure Database Savings Plan instead).
⚠️ Availability varies by SKU and region. Always verify in the Azure portal or via the Azure Retail Pricing API before purchasing.
Archera
Azure Cosmos DB is within Archera's commitment management scope. Archera can automate RU/s reservation purchase across APIs, monitor throughput utilization, and wrap commitments in a GRI/GSP — eliminating downside risk on over-committed provisioned throughput.
Sources
⚠️ Discount percentages shown are from published Microsoft documentation and vary by RU/s size and write configuration. Always verify with the Azure Pricing Calculator.
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