Choosing a DTU-based service tier, performance level, and storage resources

Service tiers are differentiated by a range of performance levels with a fixed amount of included storage, fixed retention period for backups, and fixed price. All service tiers provide flexibility of changing performance levels without downtime. Single databases and elastic pools are billed hourly based on service tier and performance level.


SQL Database Managed Instance, currently in public preview does not support a DTU-based purchasing model. For more information, see Azure SQL Database Managed Instance.

Choosing a DTU-based service tier

Choosing a service tier depends primarily on business continuity, storage, and performance requirements.

Basic Standard Premium
Target workload Development and production Development and production Development and production
Uptime SLA 99.99% 99.99% 99.99%
Backup retention 7 days 35 days 35 days
CPU Low Low, Medium, High Medium, High
IO throughput (approximate) 2.5 IOPS per DTU 2.5 IOPS per DTU 48 IOPS per DTU
IO latency (approximate) 5 ms (read), 10 ms (write) 5 ms (read), 10 ms (write) 2 ms (read/write)
Columnstore indexing N/A S3 and above Supported
In-memory OLTP N/A N/A Supported

Single database DTU and storage limits

Performance levels are expressed in terms of Database Transaction Units (DTUs) for single databases and elastic Database Transaction Units (eDTUs) for elastic pools. For more on DTUs and eDTUs, see What are DTUs and eDTUs?

Basic Standard Premium
Maximum storage size 2 GB 1 TB 4 TB
Maximum DTUs 5 3000 4000

Elastic pool eDTU, storage, and pooled database limits

Basic Standard Premium
Maximum storage size per database 2 GB 1 TB 1 TB
Maximum storage size per pool 156 GB 4 TB 4 TB
Maximum eDTUs per database 5 3000 4000
Maximum eDTUs per pool 1600 3000 4000
Maximum number of databases per pool 500 500 100


More than 1 TB of storage in the Premium tier is currently available in all regions except the following: West Central US, China East, USDoDCentral, Germany Central, USDoDEast, US Gov Southwest, USGov Iowa, Germany Northeast, China North. In other regions, the storage max in the Premium tier is limited to 1 TB. See P11-P15 Current Limitations.

Next steps