Dia — The Complete Guide: Free Flowcharts, Process and Network Diagrams on Your Own Computer

Dia is an open-source diagram editor that comes from the GNOME world. Instead of drawing free shapes, you pick symbols from ready-made libraries and join them with lines that snap to connection points — so the diagram stays tidy even when you move components around. The program is small, runs on Windows, macOS and Linux, and needs no account or network connection.

Dia

GNOME Project

A diagram editor for flowcharts, network and process drawings.

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What you get

Symbol libraries — flowcharts, UML, computer networks, electrical symbols and chemical engineering symbols.
Smart connectors — lines that stay attached to shapes as you move them.
Layers — separating parts of the diagram and hiding them temporarily.
Wide export — PNG, SVG, EPS and other formats for reports.
Open format — files are saved as XML that can be read and processed by a script.

Who it suits

Engineers and students who need a process diagram, a control schematic or a flowchart for a report — and prefer a simple local tool. The interface is somewhat dated, and for complex diagrams with polished styling there are more convenient tools.

Related tools

For a more modern interface with large libraries — diagrams.net. For diagrams generated automatically from text — Graphviz. For tidy electrical drawings with wiring lists — QElectroTech.