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KiCad

Simulating a KiCad board

KiCad has an ngspice integration, and it simulates the schematic. That answers “does this circuit work” but not “does this layout work”, because a schematic has no copper in it. Amptrace simulates the layout: the .kicad_pcb itself, tracks, vias, pours and all.

The example project's own copper, solved and coloured by current.

What it reads

A custom s-expression parser reads .kicad_pcb, .kicad_sch, .kicad_pro directly, versions 6 through 9. No KiCad installation is involved and there is no plugin to install. You hand it the files, in a browser tab or the desktop app, and it builds the board model from them.

Bring the schematic as well as the board if you have it. The board file knows which pad is on which net; the schematic knows what each pin is called and which parts are marked do-not-populate, and both change the answer. Upload every sub-sheet: a hierarchical design that arrives one sheet short is missing the part of the netlist that sheet carried.

What it does with them

  • Current per track and via, solved per segment on the real geometry, with trace width and via loading checked against IPC-2221. There is a standalone calculatorfor the single-track version of that sum.
  • Voltage per net and the drop along the copper, including across a plane, which is where a hand calculation gives up.
  • Heat: dissipation per part and the temperature field over the board.
  • Transient: inrush, PWM and settling over time, with the heatmap animating through it.
  • Design rule checks that read the solve rather than the netlist: missing pull-ups and decoupling, ESD on exposed I/O, shorts and open copper, footprint sanity, DFM. The full list.

What it is not

It is not a KiCad plugin, not a replacement for KiCad's own ERC or DRC, and not a schematic-level SPICE front end. To sweep an op-amp's response, use KiCad's ngspice, which is already installed. Amptrace is for the question that comes after the schematic is right: whether the copper you drew can carry what the circuit asks of it.

Altium, Eagle, ODB++ and bare gerbers work the same way; the import section has the specifics for each, including what gets reconstructed when all you have is gerbers.

Open a .kicad_pcb No account needed. Your board never leaves your machine.