Buyer's guide

9 best free circuit simulators in 2026

Updated August 3, 2026  ·  By the CircuitSim team  ·  15 min read

A circuit simulator predicts how a circuit will behave before you build it: the voltages, the currents, the waveforms you would otherwise find with a soldering iron and a multimeter. What changed recently is where that happens. Analysis that used to need an installed desktop application now runs in a browser tab on hardware as modest as a Chromebook, and the best free tools are no longer cut-down versions of paid ones.

This guide compares the nine most-used free circuit simulators in 2026 on the things that decide which one you should pick: real SPICE engine or simplified models, browser or desktop, install friction, classroom fit, long-term viability, and what "free" actually covers.

You are probably wondering: isn't this published on CircuitSim's website? Yes it is. We have a horse in this race, and you will not be shocked to hear we think it is a good one. We have tried to give every tool here a fair account, including the things they do better than us. If we got something wrong, tell us. We are a company of 2, so you will reach an actual person.

Runs in your browser. No install, no credit card.

How we compared them

Marketing pages make every simulator sound great. These are the criteria that change what a tool feels like to use day to day.

• Simulation engine. SPICE-based, meaning industry-standard and quantitatively accurate, or a simplified custom engine that is faster and friendlier but less accurate.
• Install friction. Browser-based with no signup, or download-and-install with an OS dependency.
• Component library. A handful of idealized parts, or thousands of real-world components with SPICE models behind them.
• Workflow. Does the interface assume 2026 conventions such as shareable URLs, real-time waveforms, and keyboard-first editing, or does it assume 2008?
• Classroom and collaboration. Sharing, group workspaces, seat management, instructor controls, student privacy.
• What "free" covers. Genuinely free, or free until the feature you need is behind a paywall.
• Long-term viability. Actively maintained, dormant, or being shut down.

Comparison table

The fastest way to choose is to scan this. Each tool has a deep-dive section below.

1. CircuitSim Our pick

Browser  ·  SPICE engine  ·  Free Basic plan, paid from $2.99/mo  ·  No install

Yes, this is our tool, and yes, we put it first. You probably saw that coming. We built CircuitSim because we wanted the full power of SPICE to live in a browser tab, with no downloads, no license keys, and no asking IT to install anything, wrapped in a workflow built this decade: shareable links, a public circuit gallery, real-time waveforms, and group workspaces. The simulation runs locally in your browser, so there is no server queue between you and your results.

• A full analysis set. Seven simulation types: interactive, interactive operating point, transient, AC sweep, DC operating point, DC sweep, and parameter sweep, which re-runs a DC operating point, transient, or AC sweep across a range of values stepped linearly, by decade, by octave, or from a list. Interactive mode lets you adjust a component value mid-simulation and watch the waveform respond, with oscilloscope-style triggering when you need to catch an edge.
• Schematic editor and SPICE netlist editor on the same circuit. Drag-and-drop capture with automatic wire routing, one-key tool shortcuts, and a quick-search palette for placing parts, alongside a netlist editor for anyone copying analysis directives out of a textbook. Undo, autosave, and dark mode included.
• Charts built for inspection. Multiple traces with per-trace styling, zoom and A/B cursors with delta readouts, Bode plots for AC sweeps, and digital logic lanes alongside analog traces on a shared time axis. Results export to CSV or XLSX; schematics export to PNG or PDF.
• A library of real parts. 3,000+ components across ten categories, from passives to semiconductors, with the parts teaching labs actually reach for: the 555, op-amps including an Analog Devices-derived family, 2N2222A and 2N3904 transistors, 2N7000 and IRFP240 MOSFETs, logic gates in 2 to 8 input variants, 7-segment displays with hex decoders, the 7805 and LM317.
• A custom component builder. Draw the symbol or import one from KiCad, paste a standard SPICE .model or .subckt with automatic PSpice, LTspice, and HSPICE dialect detection, choose which parameters are editable, then use it like any built-in part. Publish it for the community or keep it private.
• Groups for classrooms and teams. Shared circuits and components, member roles, private discussion spaces, and seat licensing bought by date range, so a semester is a first-class purchase rather than a forced annual contract. Volume discounts scale with seat count, seats can be reassigned when the roster changes, and schools can pay from a quote by NET-30 invoice instead of a credit card.
• Anonymous student seats. Students join a class group from a link with no email address, no personal account, and no student-data spreadsheet. Work persists across sessions, and a passphrase gets a student back into their seat on a new device. This is what keeps classrooms FERPA and COPPA compliant.
• A way out of Multisim Live. The importer takes .ms14 and .msjs files, individually or as a ZIP batch, and rebuilds the schematic rather than flattening it. Components map to real parts that simulate, and wiring, junctions, placement, rotation, net labels, probes, and comments come across. It is the fastest way to rescue circuits before September 15. Import is still marked experimental in the app, so spot-check a circuit against a result you trust.

Best for: anyone who cannot install desktop software, on Chromebooks, iPads, or managed work and school machines. Educators planning a syllabus, especially anyone replacing Multisim Live or teaching where student accounts are a non-starter. Students learning SPICE who want a tool they can keep after the course ends.

2. Falstad Circuit Simulator

Browser  ·  Simplified engine  ·  Free and open source  ·  No account

Paul Falstad's simulator has been the gateway to circuit simulation for a generation of engineers. It runs in any browser, animates current flow with moving dots, and makes something like an RC time constant visible in seconds. It is open source, completely free with no account, no ads, and no tiers, and still actively updated.

It is a teaching tool first. It uses its own simplified solver rather than a SPICE engine, the component models are idealized, and there is no manufacturer model import, no cloud saving, and no classroom management. Sharing happens through encoded URLs and text files. For learning fundamentals it has no equal. For designing a circuit you will actually build, the predicted result and the measured result will not match closely enough.

Best for: the free way to see how a circuit works. Outgrown the moment you need to design something whose performance has to match a measurement.

3. LTspice

Windows and macOS  ·  SPICE engine  ·  Free  ·  Analog Devices

LTspice has been the free SPICE simulator of choice for working analog engineers for over two decades. It started at Linear Technology and is now maintained by Analog Devices, with regular model library updates. The engine is fast, accurate, and well-tested. The catch is everything around it: the interface is dense and unforgiving for beginners, and there is no browser version, no Chromebook, no iPad, and no built-in sharing.

Where LTspice still wins outright is switching-regulator and DC-DC converter design, the category it was built to support and where Analog Devices keeps investing in detailed proprietary models. It also includes Monte Carlo and noise analysis at no cost, which browser tools, ours included, have not matched.

Best for: working analog engineers on Windows or macOS who have already climbed the learning curve, especially for switching-regulator work. If you cannot install desktop software, see our LTspice online guide.

4. Tinkercad Circuits

Browser  ·  Simplified engine  ·  Free, Autodesk account required

Tinkercad Circuits is Autodesk's browser-based simulator, packaged alongside their 3D design and coding tools, and free with an Autodesk account. It is friendly and visual: a photoreal virtual breadboard that maps one-to-one onto a physical one, with simulated Arduino and micro:bit boards you can program in blocks, C++, or Python. Tinkercad Classrooms adds assignments, co-teachers, and progress monitoring, which is why it is a default in K-12 STEM.

It is intentionally limited. There is no AC analysis, no DC sweep, and no custom model import, and the passive components are idealized, without the parasitics that make real circuits misbehave. Students hitting transistor biasing, op-amp circuits, or filter design outgrow it quickly.

Best for: K-12 STEM, absolute beginners, and Arduino-on-a-virtual-breadboard work.

5. Wokwi

Browser  ·  Firmware simulation  ·  Free tier, paid plans available

Wokwi does something the rest of this list does not. Where most simulators handle analog or basic digital circuits, Wokwi is built around microcontrollers: Arduino, ESP32, Raspberry Pi Pico, STM32, and more. You write firmware in the browser, hit play, and watch virtual hardware respond in real time, Wi-Fi simulation included. The free Community plan covers unlimited simulations and unlimited public projects; paid plans add private projects, faster builds, and VS Code integration on higher tiers.

Wokwi is not a SPICE simulator and is not trying to be. Analog accuracy is not the goal. For embedded and IoT prototyping in a browser, nothing else free comes close.

Best for: anyone prototyping a microcontroller project. Pair Wokwi with a SPICE tool when a project needs both firmware and an analog front end.

6. CircuitLab Paid

Browser  ·  Proprietary engine  ·  No permanent free tier

CircuitLab is the longest-standing polished browser simulator, with a proprietary mixed-mode engine, a good free interactive textbook, and schematic export to PDF, PNG, and SVG that makes it popular for documentation. It runs on anything with a browser, iPads included.

It does not belong on a free list without an asterisk. There is no permanent free tier, only a trial whose limits are not clearly published, and the entry-level student plan caps schematics at a component count that covers a voltage divider and an op-amp stage and not much more. Free student access generally exists only where the school itself buys a site license. Under the hood the engine is CircuitLab's own rather than standard SPICE, and model import stops at basic BJTs, MOSFETs, and diodes, so most manufacturer models stay out of reach. Check their pricing page for current numbers, since these move.

Best for: people who want a mature, documented, paid tool and whose school or employer is covering it.

7. Multisim Live Shutting down

Browser  ·  SPICE engine  ·  End of life September 15, 2026

Multisim Live was National Instruments' browser version of their professional Multisim tool, and for years it was the default answer for undergraduate courses that needed SPICE in a browser. The end is now official and dated.

One practical note on where the circuits go. Digilent points users at Multisim Desktop, which opens the files but is paid Windows software. CircuitSim is the only browser-based tool that imports .ms14 and .msjs directly. Everything else on this list means rebuilding by hand.

Best for: nothing new. Do not start new coursework or new circuits here in 2026.

8. EveryCircuit

Mobile and browser  ·  Simplified engine  ·  Limited free tier

EveryCircuit is known for its touch-friendly interface and animated waveforms. It is the simulator most likely to make a circuit feel like an interactive toy rather than engineering software, and its mobile apps are still the strongest part of the product. Pricing is simple: a modest one-time purchase or a low monthly fee covers the full feature set across web and mobile.

The free tier is meaningfully limited. Private circuits are capped at a handful of components, so anything past a voltage divider means paying or publishing your work publicly. The engine is not SPICE, so models are idealized, and development has slowed noticeably.

Best for: visual learning on a tablet or phone, especially for beginners who want something that feels like an app.

9. KiCad

Windows, macOS, Linux  ·  Built-in SPICE  ·  Free and open source

KiCad is not primarily a circuit simulator. It is an open-source PCB design suite that ships with built-in SPICE simulation and accepts standard SPICE, LTspice, and PSpice model formats. If you are doing real hardware where the schematic eventually becomes a physical board, designing and simulating in the same project is a strong workflow.

The learning curve is steep. KiCad is built for people who already know what they are doing, and the simulation features assume you understand SPICE. For pure simulation work, dedicated tools are easier. For end-to-end open-source hardware, KiCad is the standard.

Best for: anyone designing real hardware end to end, from schematic capture through simulation to PCB layout.

Frequently asked questions

Final verdict

The best free circuit simulator depends on what you are building. The short version:

• Browser-based SPICE on any device: CircuitSim is the strongest free pick in 2026, and the most direct path if you are leaving Multisim Live.
• Working analog engineer on a desktop: LTspice, especially for switching regulators.
• Microcontroller project: Wokwi.
• K-12 and absolute beginners: Tinkercad Circuits.
• Learning the fundamentals visually: Falstad.
• End-to-end PCB design with simulation in the same project: KiCad.
• Still on Multisim Live: export and migrate now. The platform is gone on September 15, 2026.

Free no longer means underpowered. Every tool above lets you do real work without paying. The differences come down to fit: what you are building, where you are building it, and how much friction you will put up with.

CircuitSim is built by Elsewhere Labs, which is Britt and Sam, for the people who would have built it themselves if they had the time. If we got something wrong in this guide, tell us. We read every reply.

No install, no credit card. Import your Multisim Live circuits in a couple of clicks.

More from CircuitSim:  Best Multisim alternatives (2026) · Save your Multisim Live circuits · LTspice online · Circuit simulator for Chromebooks · For educators · For schools · What is SPICE simulation

Multisim Live and Multisim are trademarks of National Instruments and Digilent (Emerson). Tinkercad and Autodesk are trademarks of Autodesk, Inc. LTspice is a trademark of Analog Devices, Inc. CircuitLab is a trademark of CircuitLab, Inc. EveryCircuit is a trademark of MuseMaze, Inc. Wokwi is a trademark of Wokwi Ltd. KiCad is a registered trademark of the KiCad Services Corporation. Falstad refers to the Falstad Circuit Simulator. CircuitSim is not affiliated with any of the above. Capability and pricing details reflect each tool's public documentation as of August 2026; competitor pricing changes, so check their sites for current numbers.