ngspice

At a glance

• Editor score
  7.9 / 10
• Pricing
  Free plan
• Best for
  Open-source simulation-engine developers
• Free plan
  Yes
• Paid from
  Free
• Schematic capture
  No
• Facts checked
  21 Sep 2026

• Where it wins

  • Free and open source across Windows, macOS, Linux, and API use
  • Advanced analog, digital, mixed-signal, noise, and statistical analyses
  • Compatible with SPICE, PSPICE, LTSPICE, and HSPICE models

• Where it doesn't

  • No built-in schematic capture or visual schematic entry
  • Requires netlists and command files for design input
  • No AI features and a desktop-focused deployment model

Our verdict on ngspice

ngspice is an open-source SPICE-compatible simulator for electrical and electronic circuits. It is designed for developers and engineering workflows that need a simulation engine for analog, digital, and mixed-signal designs rather than a complete schematic-design application. The project supports local use on Windows, Linux, and macOS, along with a shared-library API for application integration. Its input model centers on netlists and command files, making it a natural fit for software-led simulation workflows.

The analysis coverage is broad. ngspice supports DC operating-point and swept DC analysis, AC small-signal frequency analysis, transient time-domain analysis, pole-zero, distortion, sensitivity, and noise analyses. It also includes Monte Carlo and statistical circuit analysis, plus Verilog-A compact device models through OSDI/OpenVAF. Verilog and VHDL mixed-signal co-simulation extends its scope beyond conventional analog SPICE work, while compatibility with SPICE, PSPICE, LTSPICE, and HSPICE models can help fit existing model-based workflows.

Its ecosystem is strongest when paired with other tools. Integrations include KiCad, Verilator, GHDL, and OpenVAF, and the project recommends external schematic tools such as KiCad because ngspice has no built-in schematic entry. That boundary is central to the buying decision: choose ngspice for a free, open-source simulation core with extensive analysis and model support, especially when API integration or co-simulation matters. Choose another application if schematic capture and an integrated design environment are essential to the workflow.

Your product? Our editors can test ngspice in depth and publish a review, labelled as paid · from $149/mo →

ngspice pricing

ngspice fact sheet

ngspice integrations

ngspice lists 4 integrations on its own site.

• KiCad
• Verilator
• GHDL
• OpenVAF

Alternatives to ngspice

• ETAPA broad electrical engineering platform for modeling, analysis, field workflows, and automation.8.9
• Trimble Electrical DesignerA standards-focused suite for calculating, validating and reporting electrical system designs.8.8
• EEEPLAN Electric P8A broad ECAD tool for structured electrical documentation and production workflows.8.7

See all ngspice alternatives →

Featured on iTechGuides

ngspice is listed in our Electrical Design Software directory. Add the badge to your site — it links back to this page.

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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

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Last updated 7 Oct 2026 · How we research and update