Circuit simulation and schematics.

Build and simulate circuits
right in your browser.

  • Design with our easy-to-use schematic editor.
  • Analog & digital circuit simulations in seconds.
  • Professional schematic PDFs, wiring diagrams, and plots.
  • No installation required! Launch it instantly with one click.
Launch CircuitLab

or watch a quick demo video

Interactive Electronics Textbook New!

Master the analysis and design of electronic systems with CircuitLab's free, interactive, online electronics textbook.

Open: Ultimate Electronics: Practical Circuit Design and Analysis

Electronics Questions and Answers

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Easy-to-use Power Tools

Easy-wire mode lets you connect elements with fewer clicks and less frustration.


Cross-window copy/paste lets you easily explore and re-mix parts of public circuits from the CircuitLab community.

Easy-wire mode screenshot

Mixed-mode circuit simulation lets you simulate analog and digital components side-by-side.


SPICE-like component models give you accurate results for nonlinear circuit effects.

Mixed-mode circuit simulation screenshot

Human-friendly formats let you enter and display values concisely, just like you would on a paper schematic.

Unit-aware expression evaluation lets you plot arbitrary signals of interest, such as differential signals or power dissipation.

Human-friendly formats screenshot

In-browser simulation and plotting lets you design and analyze faster, making sure your circuit works before ever picking up a soldering iron.

Unique circuit URLs let you easily share your work or ask for help online.

Time-domain plotting screenshot
Advanced simulation capabilities include frequency-domain (small signal) simulation, stepping circuit parameters through a range, arbitrary Laplace transfer function blocks, and more.
Frequency-domain parameter sweep screenshot

Give it a try – this is a great idea.


Amazingly user friendly and simple for even the novice hobbyist to dive into.


Browser-based circuit simulator boasts a mountain of features.


“Smart Wires” Technology:
Build your schematic faster than ever before with our unique, intelligent Smart Wires technology for connecting terminals and rearranging components.
Smart Wires
Proprietary CircuitLab simulation engine
Proprietary Simulation Engine:
An extended-precision numerical solver core plus an advanced mixed-mode event-driven simulation engine makes it easy to get simulations running quickly.
Presentation-Quality Schematics:
Print sharp, beautiful vector PDFs of your schematics, plus export to PNG, EPS, or SVG for including schematics in design documents or deliverables.
Presentation-quality schematics
Plotting engine
Powerful Plotting Engine:
Work with multiple signals easily with configurable plotting windows, vertical and horizontal markers, and calculations on signals. Export plot images for inclusion in design documents.
Rapid Symbol Creation:
Draw generic rectangular symbols for IC or system-level wiring diagrams with just a few clicks.
Custom generic rectangular symbols
Behavioral sources and expressions
Behavioral Sources & Expressions:
Experiment and iterate rapidly with programmable algebraic sources and expressions. See documentation

CircuitLab is the best editor I have ever used. Bug-free design, excellent simulation. Well done. No more using LTSpice.

— @yigitdemirag

In our product development cycle, we've used CircuitLab in more places than you might expect: optimizing our analog front-end, RF matching network analysis, improving our power supply robustness, and designing and documenting test and production fixtures.

— Pantelligent Hardware Engineering Team