Azure Database Migration Service (DMS) is the Azure-native tool for migrating databases into Azure SQL Database, Azure SQL Managed Instance, and SQL Server on Azure VMs, as well as a range of open-source engines. As of 15 March 2026 the two paths price differently: SQL Server migrations run on the modern DMS in the Azure portal (also PowerShell and Azure CLI), which is free for the migration service itself; the classic DMS resource, with its free Standard tier and its Premium tier billed per provisioned vCore-hour after a 183-day free window, now covers the open-source engines (MySQL, PostgreSQL, MongoDB). This page is the 2026 cost reference for both paths.
What changed in March 2026
The classic Azure DMS resource has exactly two pricing tiers, and the split is about downtime tolerance, not database size. It is the pricing path for the migrations still in scope of the classic service, MySQL, PostgreSQL and MongoDB, after the SQL Server scenarios retired in March 2026. The Standard tier is free and does offline (one-time) migrations: the source is quiesced or taken offline for the cutover. The Premium tier is paid (after the free window) and adds online (continuous) replication, so the application keeps running on the source while change data flows to the target, and downtime is limited to the final cutover.
Azure Database Migration Service classic tiers (verified September 2026)
| Tier | vCore options | Migration type | Price |
|---|---|---|---|
| Standard | 1, 2, 4 vCore | Offline (one-time) only | Free |
| Premium | 4 vCore (provisioned) | Offline and online (continuous) | Per vCore-hour; free for first 183 days |
The free Standard tier covers a large share of real migrations. Any workload that can tolerate a maintenance window equal to the full-load duration (a few hours for most mid-sized databases) can migrate on the Standard tier at zero tool cost. The Premium tier only earns its keep when the source database cannot be taken offline for that long, which is the case for business-critical OLTP systems with tight availability requirements.
The tool is usually free
The decision is driven by one variable: how long the source database can be offline during cutover. If a several-hour maintenance window is acceptable, the Standard tier migrates the database for free. If the workload needs near-zero-downtime cutover (continuous replication while the source stays live), the Premium tier is required. Because Premium is free for the first 183 days on a 4-vCore service, the practical cost of choosing Premium is also zero for any migration that finishes inside that window.
Azure DMS tier selection by downtime tolerance
| Scenario | Tier | Tool cost | Notes |
|---|---|---|---|
| Database can be offline for the full-load window | Standard | Free | Most non-critical and reporting workloads |
| Near-zero-downtime cutover required | Premium | Free for 183 days | Business-critical OLTP; continuous replication |
| Migration runs longer than 183 days | Premium | Per vCore-hour after day 183 | Rare; usually signals a stalled migration |
The DMS tool is rarely the line that drives an Azure database migration budget. The dominant cost is the destination Azure SQL Database or Azure SQL Managed Instance compute, which begins billing the moment the target is provisioned and runs indefinitely afterwards. During the migration there is also a parallel-running window where both the source database and the target Azure SQL are live, doubling the database spend for the cutover period.
For heterogeneous migrations (for example Oracle or IBM Db2 to Azure SQL), the largest single cost is the schema-conversion remediation labour, the work of fixing objects that do not automatically convert from the source engine to the target. That labour is partner-led and typically runs into five or six figures per database, dwarfing the free DMS tool. The discipline for Azure DMS budgeting is to treat the tool as free and concentrate on the destination compute, the parallel-running window, and any conversion labour.
The two clouds bill their database-migration tooling on different models. AWS DMS provisions a replication instance priced like EC2 (a standard dms.r5.large is about $0.176 per hour) plus storage, billed from the first hour of use. Azure DMS gives the Standard tier away for free and gives the Premium tier free for the first 183 days, then bills per provisioned vCore-hour. The net effect: for short offline migrations Azure is free where AWS still bills instance hours, and for long online replications the two converge once the Azure free window expires. In both clouds the tooling cost is a rounding error next to the destination database compute and any conversion labour.
Database-migration tooling, Azure DMS vs AWS DMS (June 2026)
| Dimension | Azure DMS | AWS DMS |
|---|---|---|
| Free offline tier | Yes (Standard, 1/2/4 vCore) | No (instance billed from hour one) |
| Free online window | 183 days (Premium 4 vCore) | No |
| Billing unit after free window | Per provisioned vCore-hour | Per replication-instance-hour + storage |
| Serverless / auto-scaling option | No (provisioned vCore) | Yes (DMS Serverless, per DCU-hour) |
| Dominant real cost | Target Azure SQL compute | Target RDS/Aurora compute |
Azure DMS now has two distinct paths. Classic DMS (the Standard/Premium tiers above) had its SQL Server scenarios, migrations to Azure SQL Database, Azure SQL Managed Instance and SQL Server on Azure VMs, retired on 15 March 2026; new classic SQL Server resources have not been creatable since 1 August 2023. Those SQL Server migrations now run on the modern DMS, reached through the Azure portal, PowerShell or Azure CLI, which is free to use for the migration service itself, with charges only for the Azure resources the migration consumes and the destination Azure SQL. The classic Standard and Premium tiers are out of scope of the SQL retirement and continue to price MySQL, PostgreSQL and MongoDB migrations. For planning purposes the cost story is, if anything, cheaper than before: SQL migration tooling is now free, and the destination Azure SQL compute remains the cost that runs.
Azure Database Migration Service is one of the few migration tools that is genuinely free for most projects: free for offline migrations on the Standard tier, and free for the first 183 days of online migration on the Premium tier. The cost discipline for Azure DMS is not about the tool at all; it is about the destination Azure SQL compute, the length of the parallel-running window, and the conversion labour for heterogeneous sources.
A. It depends on the source. As of 15 March 2026, SQL Server migrations (to Azure SQL Database, Azure SQL Managed Instance, or SQL Server on Azure VMs) run on the modern DMS in the Azure portal, which is free for the migration service; you pay only for the Azure resources the migration consumes and the destination Azure SQL. Open-source migrations (MySQL, PostgreSQL, MongoDB) still use the classic DMS resource: the Standard tier (1, 2, and 4 vCore) is free for offline migrations, and the Premium tier is billed per provisioned vCore-hour for online migrations but is free for the first 6 months (183 days) on a 4-vCore service. Either way the DMS tool itself is effectively free; the cost that matters is the destination Azure SQL compute.
A. Yes. Azure Database Migration Service (classic) for SQL Server scenarios retired on 15 March 2026, and no new classic SQL Server resources could be created after 1 August 2023. SQL Server migrations now use the modern DMS through the Azure portal, PowerShell or Azure CLI. The modern SQL migration service is free to use; costs are limited to the Azure resources the migration consumes (for example blob storage for backups) and the destination Azure SQL. The classic Standard and Premium tiers remain only for MySQL, PostgreSQL and MongoDB, which were out of scope of the SQL retirement.
A. For SQL Server migrations, yes: the modern DMS in the Azure portal is free to use for the migration service, and you pay only for the Azure resources it consumes and the destination Azure SQL. For the classic resource (MySQL, PostgreSQL, MongoDB), the Standard tier is free for all three vCore sizes (1, 2, 4 vCore) and covers offline, one-time migrations, and the Premium tier that adds online continuous replication is free for the first 183 days on a 4-vCore service, billing per provisioned vCore-hour only beyond that window. Because most database migrations complete well inside 183 days, the tool is free in practice for the majority of projects.
A. The Standard tier supports offline (one-time) migrations only: the source database is taken offline or quiesced for the duration of the cutover. It is free across 1, 2, and 4 vCore sizes. The Premium tier adds online (continuous) migration, where change data is replicated while the source stays live, so the cutover downtime is measured in minutes rather than the full-load duration. Premium is the tier for business-critical workloads that cannot tolerate a long offline window; it is billed per provisioned vCore-hour after the 183-day free period.
A. The two services bill differently. AWS DMS charges for a provisioned replication instance (priced like an EC2 instance, for example dms.r5.large at about $0.176 per hour) plus storage, from the first hour. Azure DMS gives away the Standard tier entirely and gives the Premium tier free for the first 183 days, then bills per provisioned vCore-hour. For a short offline migration, Azure DMS Standard is free where AWS DMS still bills instance hours; for long online replications the gap narrows once the Azure 183-day window expires. In both clouds the tooling cost is small relative to the destination database compute and any schema-conversion labour.
A. The DMS tool is rarely the line that matters. The dominant costs are the destination Azure SQL Database or Azure SQL Managed Instance compute (which starts billing the moment the target is provisioned and runs indefinitely), the parallel-running window where source and target both run during cutover, and any schema-conversion remediation for heterogeneous migrations (for example Oracle or Db2 to Azure SQL). Budget the DMS tool at or near zero and put the modelling effort into the target compute tier and the length of the parallel-running window.
A. Yes, through the Premium tier. Premium performs an initial full load and then continuously replicates changes from the source until cutover, so the application downtime is limited to the final cutover step rather than the whole migration. The Standard tier does not do continuous replication; it is offline only. If a workload cannot tolerate a long offline window, the Premium tier (free for the first 183 days on 4 vCore) is the right choice.
Azure migration cost calculator ->
Hybrid Benefit, FastTrack, the full bill
Azure Migrate cost ->
Free assessment, ASR, DMS tiers
AWS DMS pricing ->
The AWS counterpart, instance-billed
On-prem to Azure ->
Hybrid Benefit, FastTrack, 3-year bill
SQL Server to AWS RDS ->
Cross-cloud database comparison
Schema conversion cost ->
The six-figure heterogeneous line
AWS vs Azure vs GCP ->
Side-by-side on one scenario
10 hidden costs ->
Parallel running and the rest
Updated 2 May 2026