Choose Oracle when you run mission-critical enterprise systems and want one vendor's converged database, Exadata hardware and support across OCI, AWS, Microsoft Azure and Google Cloud. Choose PostgreSQL when you want a free, open source database you can run on any major operating system without a free edition's resource limits. Oracle's free route is sized for learning and building: Oracle AI Database 26ai Free lets you use up to 2 CPUs, 2 GB of RAM and 12 GB of storage for your data.
Oracle now markets its database as Oracle AI Database, with the current release called 26ai, so I read its main database page and the Free edition page alongside PostgreSQL's about, licence and versioning pages.
Oracle and PostgreSQL at a glance
| Oracle AI Database | PostgreSQL | |
|---|---|---|
| Maker | Oracle | The PostgreSQL Global Development Group |
| Current release | Oracle AI Database 26ai | PostgreSQL 18 in the current docs |
| Free option (as of October 2026) | 26ai Free, up to 2 CPUs, 2 GB RAM and 12 GB of data; Always Free Autonomous AI Database on OCI | The whole project, free and open source |
| Where it runs | OCI, AWS, Microsoft Azure, Google Cloud, Cloud@Customer or on premises | All major operating systems |
| Hardware option | Exadata and Oracle Database Appliance | Not tied to a vendor's hardware |
| Licence | Oracle's own terms, with free use terms for the Free edition | PostgreSQL License, similar to BSD or MIT |
| Support rhythm | Not set out on the pages I read | Yearly major version, each supported for five years |
The ceiling on Oracle's free edition
Oracle's Free page is enthusiastic, and the offer is real: Oracle AI Database 26ai Free comes as a ready-to-go package for Linux, Windows x64, Arm and Mac developers through a Docker image, with modern data types, AI Vector Search and broad LLM support built in. There's also an Always Free Autonomous AI Database on Oracle's cloud and a browser sandbox at freesql.com.
The limits are the thing to note. Up to 2 CPUs, 2 GB of RAM and 12 GB of user data is plenty for learning and prototypes, but a production system that outgrows those numbers moves off the Free edition. PostgreSQL has no equivalent ceiling, because its licence lets you use the full software for any purpose.
Oracle's pitch: one converged engine with AI inside
Oracle says its AI Database unifies data models and workloads in a single converged engine, which it presents as a cure for data sprawl. It natively builds AI into your business data, runs where your applications live across OCI, AWS, Azure and Google Cloud, and supports open standards such as SQL, REST, JavaScript and Apache Iceberg to avoid lock-in. For on-premises work it points to Exadata and Oracle Database Appliance, and for security it lists built-in encryption, access controls, masking and database-native AI guardrails.
At the other end of the scale, our SQLite vs PostgreSQL comparison covers SQLite.
PostgreSQL's pitch: open, extensible and predictable
PostgreSQL's case rests on openness. Its licence is a liberal open source licence similar to BSD or MIT, and the project says it's committed to keeping PostgreSQL free and open source in perpetuity, with no plans to change the licence. You can define your own data types and functions, add extensions such as PostGIS, and rely on a published schedule: about one major version a year, minor fixes at least every three months and five years of support per version. Version 18 meets at least 170 of the 177 mandatory SQL:2023 Core features.
Another commercial database is set against PostgreSQL in our SQL Server vs PostgreSQL comparison.
Questions to ask before you choose
- Is this a mission-critical system where one vendor must answer for the database and the hardware? Oracle's Exadata route covers that.
- Do you need AI Vector Search from the database vendor out of the box? Oracle builds it into 26ai.
- Will your data pass 12 GB? Oracle's Free edition won't hold it; PostgreSQL has no such cap.
- Do you want to avoid licence negotiations entirely? PostgreSQL's licence lets you use it for any purpose.
- Are you already running Oracle applications? Staying on Oracle keeps support in one place.
If a move is on the cards, my guide to database migration services is a good next read, and whichever database you pick, protect it against SQL injection attacks.
Want AI doing the heavy lifting in your marketing?
I build the systems that handle the boring 80 percent, so you get your week back. Done properly, with the human kept in.
My advice on Oracle or PostgreSQL
For a small or mid-sized business starting fresh, I'd choose PostgreSQL: it's free at any size, runs anywhere and has a clear support schedule. Oracle makes sense when you already run Oracle systems, need its converged engine and Exadata for demanding workloads, or want one company to stand behind the whole stack across several clouds. If you're curious about Oracle's AI features, the 26ai Free edition is a no-risk way to try them before any commitment.
Do you make database tools? Tool makers can ask to be considered for a featured place in comparisons like this one.
Frequently asked questions
Is Oracle Database free?
Oracle AI Database 26ai Free is free to download and use within limits of up to 2 CPUs, 2 GB of RAM and 12 GB of user data. Oracle also offers an Always Free Autonomous AI Database on its cloud.
What is Oracle AI Database 26ai?
It's the name Oracle uses for its current database release, which it describes as architecting AI into the core of data management, including AI Vector Search.
Where can Oracle AI Database run?
Oracle says it runs across OCI, AWS, Microsoft Azure and Google Cloud, in your data centre with Cloud@Customer, or on premises on Exadata and other supported infrastructure.
Is PostgreSQL free for businesses?
Yes. PostgreSQL is released under the PostgreSQL License, a liberal open source licence that its project describes as similar to BSD or MIT.
How often does PostgreSQL release new versions?
The PostgreSQL Global Development Group releases a new major version about once a year and supports each one for five years.
