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Qucs-S vs ngspice: catalog facts
Qucs-S	ngspice
Free Free and open source, supported by donations.	Free Free and open source.
Windows, macOS, Linux	Command line
Graphical schematic entry for SPICE simulation Windows installer bundles Ngspice	Analog, digital and mixed-signal simulation Accepts PSPICE and LTSPICE device models
Simulation only; no PCB layout macOS install goes through Homebrew	No built-in schematic entry Netlist and command-line workflow has a learning curve
Downloadable app	Downloadable app
Open source	Open source
License: GPL-2.0	License not stated
No account needed	Not stated if an account is needed
Works offline	Not stated if it works offline
Official website Full listing and sources Checked September 23, 2026	Official website Full listing and sources Checked September 23, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.