FreeDiagram
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Free ER Diagram Maker

Describe your database schema in plain English and FreeDiagram draws the entity-relationship diagram instantly — entities, attributes, and relationships included. Free, unlimited, no signup.

ER diagram · every result is a er diagram  ·  ⌘↵ to run

Free forever · no signup · no credit card · unlimited diagrams

Live sample · E-commerce database schema — type above to make your own
E-commerce Schema Entity-Relationship Diagram with 6 entities and 5 relationships. E-commerce Schema places Customer customer_id int PK email varchar UK name varchar created_at timestamp Category category_id int PK name varchar Address address_id int PK customer_id int FK line1 varchar city varchar Order order_id int PK customer_id int FK placed_at timestamp status varchar Product product_id int PK category_id int FK name varchar price decimal OrderLine order_id int PK FK line_no int PK product_id int FK qty int

An entity-relationship (ER) diagram maps the structure of a database by showing its entities (tables), their attributes (columns), and the relationships between them. Whether you are designing a new schema from scratch or documenting an existing database, a clear ER diagram is the fastest way to align your team and spot missing relationships before writing a single line of SQL. FreeDiagram reads your plain-English description and produces a properly structured ER diagram in seconds — no diagram tool subscription required.

How to make an ER diagram in seconds

  1. Describe your data model

    List the main entities (tables) and mention key relationships — e.g. 'users have many orders, each order has many line items, orders belong to customers'.

  2. FreeDiagram draws the schema

    The AI identifies entities, attributes, and cardinality, then renders a clean ER diagram with crow's-foot notation — primary keys, foreign keys, and relationship lines included.

  3. Review and refine

    Add missing tables, tweak relationships, or specify cardinality by adjusting your description and regenerating instantly — each run is free and takes seconds.

  4. Export as SVG or PNG

    Download a sharp, watermark-free vector SVG or high-resolution PNG for documentation, presentations, or sharing with your engineering team.

What is an ER diagram and when should you use one?

An entity-relationship (ER) diagram is a visual blueprint of a relational database. Introduced by Peter Chen in 1976, it has become the standard tool for database design across software engineering, data architecture, and academic computer science.

In an ER diagram, entities represent tables, attributes represent columns, and relationship lines show how tables connect. Modern teams typically use crow's-foot (IE) notation: entities are boxes listing their fields, primary keys are marked PK, and relationship lines carry cardinality markers — one-to-one (1:1), one-to-many (1:N), or many-to-many (M:N).

ER diagrams are valuable at every stage of development. During design, they help teams agree on the data model before writing migrations. During code review, they make schema changes immediately visible to non-database engineers. During onboarding, they let new members understand the data architecture at a glance without reading raw SQL.

AI generation changes the workflow significantly. Instead of dragging entity boxes and drawing relationship lines, you describe the domain in natural language — 'a SaaS app with users, teams, subscriptions, and invoices' — and the diagram appears instantly. This is especially useful for rapid prototyping, stakeholder reviews, and early-stage architecture discussions where speed matters more than perfect precision.

FreeDiagram supports ER diagrams of any complexity, from simple three-table schemas to multi-domain enterprise models. Generate a working first draft in seconds, then refine iteratively by adjusting your description and regenerating.

Frequently asked questions

Is the ER diagram maker free?

Yes — completely free, unlimited generations, no signup or credit card required. The site is funded by display advertising.

What notation does the ER diagram use?

FreeDiagram uses crow's-foot (IE) notation by default — the most common style in modern software teams. Entities are boxes, and relationship lines carry cardinality markers showing one-to-many or many-to-many relationships.

Can I export the diagram for documentation?

Yes. Download as SVG for crisp vector graphics that scale to any size, or PNG for raster images. Both formats are watermark-free and free to use.

How specific should my description be?

Listing the main tables and their key relationships gives the best results. Mentioning primary keys, foreign keys, or cardinality (one-to-many, many-to-many) produces a more complete and accurate diagram.

Can FreeDiagram handle many-to-many relationships?

Yes. Describe the relationship naturally — 'students enroll in many courses, and each course has many students' — and FreeDiagram will model it correctly, often adding a junction table automatically.

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