Top Free Online Circuit Simulators for Engineers & Hobbyists (2026)

Testing electronic designs before building physical hardware saves time, reduces component burnout, and accelerates prototyping. Web-based circuit simulation tools allow engineering students, educators, and hobbyists to design, analyze, and test analog and digital circuits directly from a web browser without installing heavy desktop software.

This guide reviews the top free online circuit simulators , comparing their features, simulation engines, and ideal use cases.

1. Wokwi Simulator

Best For: ESP32, Raspberry Pi Pico, STM32, and Arduino IoT simulation with Wi-Fi/MicroPython support.

Wokwi is an advanced browser-based simulator designed for embedded systems and IoT development. It allows developers to simulate microcontrollers like the ESP32, Raspberry Pi Pico, and Arduino Uno alongside real-time network connectivity and digital peripherals.

Key Features

• Multi-Architecture Support: Simulates ESP32, Raspberry Pi Pico (RP2040), STM32, and ATmega328P (Arduino).
• Wi-Fi & Network Simulation: Simulates virtual Wi-Fi connections for ESP32 HTTP/MQTT IoT projects directly in the browser.
• MicroPython, Rust & C++ Support: Program using standard C++ in the Arduino framework, MicroPython, or Rust.
• Declarative JSON Layout: Circuit connections can be configured graphically or via a simple diagram.json file.

2. Autodesk Tinkercad Circuits

Best For: Beginners, STEM education, and basic visual breadboard setup.

Autodesk Tinkercad Circuits provides an intuitive visual interface featuring realistic breadboards, batteries, passive components, and microcontrollers like the Arduino Uno.

Key Features

• Visual Breadboard Layout: Connect components as you would on a physical workbench.
• Microcontroller Simulation: Supports block-based and C/C++ coding for Arduino with an integrated Serial Monitor.
• Interactive Controls: Toggle switches, adjust potentiometers, and observe LED responses in real time.

3. Falstad Circuit Simulator

Best For: Understanding fundamental AC/Analog electronics and real-time signal visualization.

Falstad is an open-source, lightweight Java/JavaScript circuit simulator running smoothly in any web browser. Its defining feature is animated visual current flow, where moving dots illustrate current speed and direction across components.

Key Features

• Real-Time Visual Feedback: Instant visual animation of current, voltage drops, and frequency response.
• Extensive Example Library: Pre-built schematics covering RC/RLC filters, operational amplifiers, logic gates, and transformers.
• Scope Traces: Integrated virtual oscilloscope traces beneath the schematic for voltage and current analysis.

4. EasyEDA

Best For: Seamless transition from SPICE simulation to PCB layout and manufacturing.

EasyEDA is a web-based EDA (Electronic Design Automation) tool suite that combines schematic capture, ngspice-based circuit simulation, and PCB design in a unified interface.

Key Features

• SPICE Engine Integration: Run transient analysis, DC sweeps, and AC frequency analysis using standard SPICE models.
• Extensive Component Library: Millions of public schematic symbols and footprints linked to real component suppliers.
• Direct PCB Conversion: Easily convert verified schematics directly into multi-layer PCB layouts.

5. Cirkit Designer

Best For: Modern component-level circuit schematics and interactive design.

As noted in recent updates from Cirkit Design (referenced via Cirkit Design Updates), platforms like Cirkit Designer focus on providing accessible breadboard diagramming paired with component-level simulation models.

Key Features

• High-Quality Diagramming: Clean graphical representations suitable for documentation and tutorials.
• Component-Level Simulation: Expanding library covering common maker components and microcontrollers.
• Community-Driven Models: Ecosystem options for contributing custom component definitions.

6. EveryCircuit

Best For: Interactive mobile and web circuit exploration with dynamic waveform animations.

EveryCircuit features a polished graphical engine that animates charge movement, voltage nodes, and component power dissipation dynamically as circuit parameters change.

Key Features

• Interactive Parameter Tuning: Adjust component values (such as capacitance or frequency) using an interactive dial and watch the circuit adapt immediately.
• Cross-Platform Synchronization: Access designs across web browsers and mobile devices.
• Community Gallery: Browse thousands of public community-created circuit schematics.

7.Velxio Simulator

Best For: Open-source, multi-board CPU emulation and integrated SPICE analog co-simulation.

Velxio (discussed in detail in the Velxio ESP32 Simulation Overview) is an open-source, web-based embedded simulator and electronic circuit emulator. It combines cycle-accurate CPU instruction emulation with an ngspice WebAssembly engine for hybrid analog and digital co-simulation, as highlighted in its Technical Architecture Overview.

Key Features

• Real CPU Architecture Emulation: Runs authentic firmware binaries across 30+ boards, including ESP32 (Xtensa/RISC-V via QEMU), Raspberry Pi Pico (RP2040), STM32, and Arduino AVR.
• ngspice-WASM Co-Simulation: Simulates real analog circuit behavior alongside microcontrollers using an embedded WebAssembly-compiled SPICE engine.
• Open-Source & Self-Hostable: Can be run on hosted web instances or self-hosted locally using Docker containers.
• Language Flexibility: Supports compilation for C/C++ (via standard Arduino CLI and ESP-IDF chains), MicroPython, and Rust.

Comparison Summary

How to Choose the Right Online Simulator

1. For IoT & Advanced Microcontrollers (ESP32, Pico): Use Wokwi for network simulation, Wi-Fi connectivity testing, and MicroPython/C++ code execution.
2. For Beginners & STEM Students: Start with Tinkercad Circuits or Electronics Beginner Arduino Projects references for drag-and-drop breadboarding.
3. For Circuit Theory & Visualization: Use Falstad or EveryCircuit to visualize current flows and signal waveforms.
4. For Hardware Prototyping & PCB Design: Choose EasyEDA when preparing custom schematics for PCB fabrication.

Wokwi Project Configuration Example

If you want to set up an Arduino Uno LED Blink circuit in Wokwi, you can use the following diagram.json configuration file:

JSON

{
  "version": 1,
  "author": "Elecblog",
  "editor": "wokwi",
  "parts": [
    { "type": "wokwi-arduino-uno", "id": "uno", "top": 0, "left": 0 },
    { "type": "wokwi-led", "id": "led1", "top": -60, "left": 120, "attrs": { "color": "red" } },
    { "type": "wokwi-resistor", "id": "r1", "top": -20, "left": 120, "attrs": { "value": "220" } }
  ],
  "connections": [
    [ "uno:GND.1", "led1:C", "black", [ "v0" ] ],
    [ "uno:13", "r1:1", "green", [ "v0" ] ],
    [ "r1:2", "led1:A", "green", [ "v0" ] ]
  ]
}