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ngspice

ngspice.sourceforge.io

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Spec score 8.2 #21 of 89 in Physics Simulation Software

What it is

ngspice is a free, open-source simulator for electric and electronic circuits described as netlists. It handles analog, digital, and mixed-signal designs, with models for active, passive, analog, and digital elements; model parameters can come from collections, manufacturers, or foundries. Its SPICE compatibility supports PSPICE or LTSPICE device model parameters and netlists for discrete circuits. For mixed-signal co-simulation, it supports Verilog blocks compiled with Verilator and, since ngspice-44, VHDL blocks using GHDL. The OSDI/OpenVAF interface connects Verilog-A compact device models without requiring programming on the ngspice side. It can also be built as a shared library or DLL for another application to control. Listed integrations include KiCad, Autodesk Fusion, and Python interfaces such as PySpice. ngspice does not include schematic entry: input is through the command line or files. The stable download page offers source archives and Windows binaries; Linux users are directed to their distributor or source compilation, and the project's own macOS release is unavailable there.

Spec sheet

Purpose
ngspice is an open-source simulator for electric and electronic circuits.Read 7 Oct 2026 · ngspice.sourceforge.io
Platforms
The source compiles on Linux, Windows, Mac, BSD, and Solaris; the download page also points macOS users to Homebrew.Read 7 Oct 2026 · ngspice.sourceforge.io
Free plan
YesRead 21 Sep 2026 · ngspice.sourceforge.io
Support
The project offers mailing lists, discussion forums, a bug tracker, an FAQ, and documentation.Read 7 Oct 2026 · ngspice.sourceforge.io
Circuit types
It simulates analog, digital, and mixed-signal circuits described in netlists.Read 7 Oct 2026 · ngspice.sourceforge.io
Compatibility
It is SPICE-compatible and can use PSPICE or LTSPICE device model parameters and netlists for discrete circuits.Read 7 Oct 2026 · ngspice.sourceforge.io
Downloads
The stable download page offers source archives and Windows binaries, while noting that Linux users should use their distributor or compile from source and that its own macOS release is currently unavailable there.Read 7 Oct 2026 · ngspice.sourceforge.io
Input limitation
ngspice does not provide schematic entry; its input is command-line or file-based.Read 7 Oct 2026 · ngspice.sourceforge.io
Mixed-signal integration
It supports mixed-signal co-simulation with Verilog blocks compiled using Verilator and, since ngspice-44, VHDL blocks using GHDL.Read 7 Oct 2026 · ngspice.sourceforge.io
Model integration
The OSDI/OpenVAF interface integrates Verilog-A compact device models without requiring programming on the ngspice side.Read 7 Oct 2026 · ngspice.sourceforge.io
Models
It provides device models for active, passive, analog, and digital elements, and can use model parameters from collections, manufacturers, and foundries.Read 7 Oct 2026 · ngspice.sourceforge.io
Programming
ngspice can be compiled as a shared library or DLL for control by a calling application.Read 7 Oct 2026 · ngspice.sourceforge.io
Third-party integrations
The project lists integrations with KiCad, Autodesk Fusion, and Python interfaces including PySpice.Read 7 Oct 2026 · ngspice.sourceforge.io

Plans and prices

ngspice Free Free Circuit simulator; command-line or file-based input; no schematic entry Read 7 Oct 2026 · ngspice.sourceforge.io

Every ngspice plan and price →

Strong points and limits

Strong points

  • Free and open source.
  • Supports analog, digital, and mixed-signal simulation.
  • Can co-simulate Verilog and VHDL blocks.
  • Can be compiled as a shared library or DLL.
  • Integrations include KiCad, Autodesk Fusion, and PySpice.

Limits

  • No schematic entry.
  • Input is command-line or file-based.
  • The project's own macOS release is unavailable on its stable download page.

Who it suits

ngspice suits users who can describe circuits as netlists and want to simulate analog, digital, or mixed-signal designs. It also fits workflows connecting simulation to other applications through a library or listed integrations.

Verdict

ngspice provides circuit simulation with support for multiple model and co-simulation workflows. It expects netlist input rather than schematic capture, so users need a command-line or file-based workflow.

Where Specifiction places it

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