Drag-and-drop schematic canvas
Place resistors, capacitors, inductors, diodes, transistors and sources on a snap-to-grid canvas. Click terminals to wire them up, drag to rearrange, and watch your schematic come together in seconds.
Free web-based SPICE simulator
Design, simulate & analyze circuits in your browser
SPICE-Online is a free online circuit simulator with a drag-and-drop schematic editor, a live SPICE netlist, real-time voltage & current plots, and an AI Circuit Assistant that builds circuits from your prompts. No install. No setup. Just open and create.
Built for the way you actually design circuits
Students
Hobbyists
Engineers
Educators
Everything in one editor
A complete circuit lab, online
From the first wire to the final waveform — design, edit and simulate without leaving your browser tab.
Live, editable netlist
The SPICE netlist stays in sync with your canvas. Edit the text and the schematic updates instantly — or draw and watch the netlist write itself.
AI Circuit Assistant
Describe what you want in plain English and the assistant places components, wires connections and configures the simulation — right on your canvas.
Real-time plotting
Run transient, DC and AC analyses and watch voltage and current graphs update in real time as the simulation steps through.
Import & export SPICE
Bring in existing SPICE files and export your work anytime. Your circuits are portable, standards-based and yours to keep.
A full component library
Resistors (R), capacitors (C), inductors (L), voltage (V) and current (I) sources, diodes (D), transistors (Q) and ground — plus a searchable library panel for everything else you need to model real circuits.
AI Circuit Assistant
Just describe it. Watch it get built.
The AI Circuit Assistant turns plain-language prompts into working circuits — placing parts at strategic spots, drawing the connections, and dialing in the simulation settings for you.
- Places & positions components automatically
- Adds, removes and rewires connections on command
- Configures the right simulation type for the job
Three steps to a simulation
From idea to waveform, fast
01
Build your circuit
Drag components onto the canvas and click terminals to wire them — or ask the AI Assistant to lay it out for you.
02
Tune the netlist
Tweak values directly in the live SPICE netlist. Every edit reflects instantly on the schematic, both ways.
03
Run & analyze
Hit Run Simulation, choose your analysis, and read voltage and current straight off real-time plots.
Simple, honest pricing
Start free. Upgrade when you grow.
Every plan runs in the browser with nothing to install. Cancel anytime.
Monthly
Yearly save 20%
Free
For learning, tinkering and one-off projects.
$0 /forever
- Drag-and-drop schematic editor
- Live, editable SPICE netlist
- DC & transient simulation
- Import & export SPICE files
- 10 AI Assistant prompts / day
Most popular
Pro
For serious designers who simulate every day.
$9 /mo
- Everything in Free
- Unlimited AI Circuit Assistant
- Real-time voltage & current plots
- AC sweep & advanced analyses
- Larger circuits & priority compute
- Export plots to PNG & PDF
Team
For classes, labs and engineering teams.
$29 /mo
- Everything in Pro
- Shared team workspaces
- Real-time collaboration
- Version history & SSO
- Priority support
Good to know
Frequently asked questions
Is SPICE-Online free to use?
Yes. You can design schematics, edit the live SPICE netlist and run simulations on the free plan with no installation. Advanced features like the unlimited AI Circuit Assistant and real-time plotting come with Pro.
Do I need to install anything?
No. SPICE-Online runs entirely in your web browser. There's nothing to download — open the editor and start building circuits on any modern device.
What is SPICE simulation?
SPICE is the standard way engineers model how electronic circuits behave. It calculates voltages and currents over time and frequency, so you can verify a design before building it on a breadboard or PCB.
Can I import my existing SPICE netlists?
Absolutely. Import standard SPICE netlist files to keep working on circuits you already have, and export anytime — your work stays portable.
What components are supported?
Resistors, capacitors, inductors, voltage and current sources, diodes, transistors and ground are built in, with more available from the library panel.
How does the AI Circuit Assistant work?
Type what you want — for example, "add a diode rectifier with a smoothing capacitor" — and the assistant places the components, wires the connections and sets up the right simulation directly on your canvas.
Start building circuits — free
Open the editor, drop your first component, and run a simulation in under a minute.
Try for Free