TL;DR: A realistic Oracle to PostgreSQL migration costs between €5,000 and €80,000+ depending on schema complexity, PL/SQL volume, and whether zero-downtime cutover is required.
The tools are free.
The cost is almost entirely consultant time, testing effort, and application changes.
Most medium-complexity migrations pay back their full cost within the first year of Oracle license savings.
Your Oracle support renewal is due.
The number is higher than last year — again.
You know PostgreSQL is mature and free.
But every time you ask what a migration would cost, you get vague answers or, worse, a six-figure quote from a large consultancy that barely covers the discovery phase.
This post gives you a realistic, structured breakdown — not a sales pitch.
Based on assessments I have run across banking, insurance, and telecoms environments in the EU, here is what migrations actually cost and what drives that number up or down.
Table of Contents
What Does an Oracle to PostgreSQL Migration Actually Cost?
Most medium-complexity migrations fall in the range of €15,000 to €50,000 in total consultant time — covering assessment, schema conversion, data migration, testing, and cutover.
Simple migrations (few schemas, minimal PL/SQL) can come in well under €15,000.
Complex migrations with heavy stored procedure logic, Oracle-specific features, or zero-downtime requirements push past €50,000.
The tools themselves cost nothing.
ora2pg, the standard Oracle-to-PostgreSQL migration tool, is open source and free.
PostgreSQL is open source and free.
Every euro of migration cost is labour: analysis, conversion, testing, and the application changes that almost always accompany a database migration.
What Goes Into the Cost?
A well-run migration has five cost components.
1. Assessment and scoping (2–3 days)
Before any migration work starts, the schema needs to be assessed: how many tables, how much PL/SQL, what Oracle-specific features are in use, what the application code depends on.
This is the most important phase — it determines everything else.
Skipping it is where migrations go over budget.
2. Schema conversion (varies by complexity)
Tables, sequences, indexes, and views convert largely automatically with ora2pg.
The manual effort is in PL/SQL: stored procedures, functions, packages, and triggers.
Every PL/SQL unit has to be reviewed, ported to PL/pgSQL, tested, and validated.
A schema with no PL/SQL converts in days.
A schema with 50 stored procedures and 10 packages converts in weeks.
3. Data migration and validation (2–5 days for a clean schema)
Moving the data is usually the least expensive phase.
ora2pg handles the extraction and generates PostgreSQL-compatible load scripts.
The cost is in validation: row counts, data type spot checks, sequence restart, and foreign key integrity after load.
4. Testing (20–30% of total project effort)
This is the component that gets underestimated most.
Functional regression testing, performance baseline comparison, and application integration testing all take time.
If the system has no existing test suite, this cost rises significantly.
5. Application changes
This is the wildcard.
Oracle SQL dialects — ROWNUM, FROM DUAL, NVL(), (+) outer join syntax, CONNECT BY hierarchical queries — all need to be replaced with PostgreSQL equivalents in application code.
For a modern application using ANSI SQL and an ORM, this is minimal.
For a legacy application with embedded Oracle SQL throughout, this can cost more than the database migration itself.
Scoping a migration and want a realistic cost estimate before committing?
I offer a fixed-fee assessment that gives you a written breakdown of complexity, effort, and risk — see what the assessment covers →
What Drives Migration Cost Up?
Heavy PL/SQL: Stored procedures, functions, packages, and triggers are the main cost driver.
Oracle PL/SQL and PostgreSQL PL/pgSQL are similar enough to be dangerous — the syntax looks familiar but the semantics differ in ways that create silent bugs.
Every unit requires manual review.
Oracle-specific features: Partitioning, Advanced Queuing, materialized view fast refresh, and Oracle Text all require architectural decisions, not just syntax conversion.
Some have direct PostgreSQL equivalents.
Some require redesign.
Zero-downtime requirement: A migration where the system must stay live during cutover requires logical replication, a dual-write or change-data-capture layer, and a significantly more complex testing and switchover procedure.
Plan for 30–50% additional cost versus a maintenance-window cutover.
Large data volumes: Migrating terabytes of data takes time and requires careful orchestration.
The conversion cost does not scale linearly with data volume, but cutover planning and validation do.
No existing test coverage: If the application has no automated tests, every functional change needs to be validated manually.
This is the single biggest hidden multiplier on testing cost.
What Drives Migration Cost Down?
Simple schema, little or no PL/SQL: If the database is used primarily as a data store with all logic in the application layer, schema conversion is fast and mostly automated.
Modern application already using ANSI SQL: An ORM-backed application using standard SQL syntax requires minimal application-side changes after the database switches.
Flexible cutover window: A maintenance-window cutover — where the application goes offline briefly during switchover — is significantly simpler and cheaper than a live cutover.
For most internal or non-consumer-facing systems, a two-hour maintenance window is acceptable.
Good test coverage already in place: Existing regression and integration tests dramatically reduce post-migration validation cost.
How Quickly Does a Migration Pay for Itself?
For most organisations, an Oracle to PostgreSQL migration pays back within the first year of licence savings.
Oracle Enterprise Edition is priced at approximately €43,000 per processor licence, plus 22% annual support fees.
A standard dual-socket server with 16 cores carries over €350,000 in base EE licences alone — before any add-on options.
Annual support on that configuration exceeds €75,000 per year.
A mid-complexity migration costing €25,000 in consultant time saves that entire annual support fee within three to four months.
The savings compound every year after that.
The companies that delay migration are not saving money.
They are paying Oracle tens of thousands of euros per year for a problem that has already been solved.
Is DIY Migration an Option?
Technically, yes.
The tools are free and the documentation is thorough.
A senior DBA with PostgreSQL experience can run a migration internally.
The risk is not the tools — it is the knowledge gaps.
Oracle and PostgreSQL behave differently in ways that are not obvious until something breaks in production: NULL handling in unique indexes, the Oracle DATE versus PostgreSQL TIMESTAMP trap, implicit type conversions that Oracle accepts and PostgreSQL rejects, PL/SQL patterns that convert syntactically but fail semantically.
An experienced migration specialist catches these before go-live.
An internal team discovers them after.
Frequently Asked Questions
How much does an Oracle to PostgreSQL migration cost?
Most medium-complexity migrations cost between €15,000 and €50,000 in total consultant time.
Simple migrations with minimal PL/SQL can come in well under €15,000.
Complex migrations with heavy stored procedures, Oracle-specific features, or zero-downtime requirements cost more.
The migration tools themselves are free — the cost is entirely in labour.
What is the biggest cost driver in an Oracle to PostgreSQL migration?
PL/SQL volume.
Stored procedures, functions, packages, and triggers require manual review and porting to PL/pgSQL.
Tables, sequences, and basic views are largely automated.
A schema with no PL/SQL and no Oracle-specific features can be migrated in days.
A schema with significant PL/SQL logic takes weeks.
How long does an Oracle to PostgreSQL migration take?
A small migration can be completed in two to four weeks of calendar time.
A medium-complexity migration typically runs eight to twelve weeks.
Complex migrations with zero-downtime requirements or heavy PL/SQL can run three to six months.
Timeline depends more on complexity and testing requirements than on data volume.
Will we save money by migrating to PostgreSQL?
In most cases, yes — substantially.
Oracle Enterprise Edition licensing plus annual support fees typically run into the tens of thousands of euros per server per year.
A migration that eliminates those fees pays back its cost within months, not years.
The savings compound every year after the first.
Can we migrate to PostgreSQL without downtime?
Yes, but it adds cost and complexity.
A zero-downtime migration requires a logical replication or change-data-capture layer to keep the PostgreSQL database in sync with Oracle during the transition period.
For most internal or non-consumer-facing systems, a planned maintenance window is simpler and more reliable.
The right approach depends on the system’s SLA requirements.
In Summary
Oracle to PostgreSQL migration is a one-time investment that eliminates a recurring licence cost that compounds every year.
The tools are free.
The cost is consultant time — primarily schema conversion, PL/SQL porting, and testing.
A well-scoped migration starts with an assessment that maps every cost driver before any work begins.
If you want to understand what a migration would cost for your specific environment, I offer a fixed-fee assessment that delivers a written complexity analysis, effort estimate, and risk register.
See what the assessment covers →