Compare software

ngspice vs Qucs-S: catalog facts
ngspice	Qucs-S
Best for: Engineers and students simulating circuits from netlists or through a schematic front end	Best for: Students and engineers who want a graphical front end for SPICE circuit simulation
Free Free and open source.	Free Free and open source, supported by donations.
Command line	Windows, macOS, Linux
Analog, digital and mixed-signal simulation Accepts PSPICE and LTSPICE device models All 3 strengths for ngspice Analog, digital and mixed-signal simulation Accepts PSPICE and LTSPICE device models Can be driven by third-party schematic tools	Graphical schematic entry for SPICE simulation Windows installer bundles Ngspice All 4 strengths for Qucs-S Graphical schematic entry for SPICE simulation Windows installer bundles Ngspice Packaged for many Linux distributions, Windows and macOS Regular releases
No built-in schematic entry Netlist and command-line workflow has a learning curve	Simulation only; no PCB layout macOS install goes through Homebrew
Downloadable app	Downloadable app
Open source	Open source
License not stated	License: GPL-2.0
Not stated if an account is needed	No account needed
Not stated if it works offline	Offline features available
Official website Full listing and sources Sources for ngspice ngspice.sourceforge.io Catalog checked September 23, 2026	Official website Full listing and sources Sources for Qucs-S ra3xdh.github.io Catalog checked September 23, 2026

“Not stated” means we have not confirmed it. Features can vary by device and plan.