Free ERD Builder Online with Chen and EER Notation
Build ER diagrams online without SQL. Use Chen notation, EER subtypes, cardinality and model checks. Export PNG, SVG or PDF; sign in to save and share.
Model a database without SQL
Add entities, weak entities, relationships, identifying relationships, key and partial-key attributes, composite, multivalued and derived attributes, ISA specializations, union categories, aggregation, and notes.
Cardinality, participation, and EER model checks
Set classic or min-max cardinality and role names. Choose partial or total participation, disjoint or overlapping ISA membership, and total or partial subtype coverage. Assign ISA and category connector roles explicitly and review live structural checks.
Design, save, and share an ERD
- Click, tap, drag, or use the keyboard to add shapes. Build connected attributes and relationships from a selection.
- Connect shapes, customize labels and cardinality, and arrange the diagram. Undo changes or lock positions as needed.
- Export the current view or entire diagram as PNG, SVG, or PDF. Sign in to save editable Builder files and share read-only public views.
Learn ERD Builder
- How to Use ERD Builder: Draw an ER Diagram Without SQL
- Chen Notation ERD Guide: Symbols, Keys, and Cardinality
- EER Diagrams in ERD Builder: ISA, Categories, and Aggregation
Builder creates conceptual diagrams and converts them to SQL through a review of relational mappings, types, and conversion notes.
Working from an existing schema? Convert SQL to an ERD or visualize a Prisma schema.