WHERE free IN ('free', 'free-edition', 'free-plan') · 14 rows
Free and open-source data modeling tools
"Free" covers three different deals: free software, a free edition with features held back, and a free plan on a hosted service with caps. Here is which is which, with the limits copied from each vendor's page.
Completely free
No paid tier needed for the core tool.
| tool | license | what the free option includes or limits |
|---|---|---|
| Oracle SQL Developer Data Modeler | Free to use (Oracle license) | Free. Oracle's FAQ answers "Is Oracle SQL Developer Data Modeler free?" with "Yes". Oracle names the levels logical, relational, physical and multi-dimensional; we map its ERD layer to conceptual. |
| Mermaid (erDiagram) | Open source (MIT) | Free and open source. Draws entities, attributes and relationships; it does not generate or read database schemas. |
| ChartDB | Open source (AGPL-3.0) | Self-hosted open-source edition is free. |
| drawDB | Open source (AGPL-3.0) | Free. |
| MySQL Workbench | Free download (Community) | Free. Applies to the legacy 8.0 line's EER modeling. |
| draw.io (diagrams.net) | Open source (Apache-2.0) | Free. |
Free edition of a paid product
A permanent free edition with features held back for paid editions.
| tool | license | what the free option includes or limits |
|---|---|---|
| DbSchema | Proprietary | The purchase page showed prices localized to our retrieval location, so we have not recorded a USD price. It lists a free Community edition, a perpetual or monthly Pro license and an Architect edition. Per the purchase page, logical and conceptual design are in the Architect edition. |
| Hackolade Studio | Proprietary | Community edition is free. Personal, Professional and Workgroup editions are compared in the vendor's feature matrix. |
| pgModeler | Open source (GPL-3.0 (Community edition)) | Plus edition is paid; a trial key is offered. We did not capture a price. |
| DBeaver | Open source (Apache-2.0 (Community edition)) | Community edition is free; commercial PRO editions exist. Prices not captured. |
Free plan of a hosted service
Free accounts with limits on documents, tables or privacy.
| tool | license | what the free option includes or limits |
|---|---|---|
| dbdiagram.io | Proprietary app; the DBML language is open source (Apache-2.0) | Free plan available indefinitely. Free Personal Pro for education for 12 months, renewable. |
| QuickDBD | Proprietary | Free plan; registration not required to try the app. |
| DrawSQL | Proprietary | Free plan: public diagrams only, up to 15 tables. |
| Lucidchart | Proprietary | Free plan: 3 editable documents, 75 shapes per document. |
Which free tool fits which job?
- Designing a relational schema from scratch, for free: Oracle SQL Developer Data Modeler is the only completely free tool here whose vendor describes logical, relational and physical modeling with forward and reverse engineering. Its strongest fit is Oracle.
- A PostgreSQL model: pgModeler Community is open source, but since 2.0 importing a live database and model diff are in the paid Plus edition.
- A quick shareable diagram in the browser: drawDB and ChartDB are open source (AGPL-3.0) and can be self-hosted; dbdiagram.io has a free plan if you prefer typing DBML.
- Diagrams that live in Git next to code: Mermaid erDiagram (MIT). You maintain it by hand; nothing syncs with a database.
- Seeing an existing database: DBeaver Community generates ER diagrams from a live connection. It's a viewer, not a design-first modeler.
editorial summary of the facts in each linked record
Open-source licenses matter if you plan to modify and host a tool for others: AGPL-3.0 (drawDB, ChartDB) and GPL-3.0 (pgModeler) carry obligations that Apache-2.0 (DBeaver, draw.io) and MIT (Mermaid) don't. This is general information, not legal advice.