Terms of Use

Effective date: 18 September 2026

By using freecircuitsim.com ("the site") you agree to these terms. If you do not agree, please do not use the site.

What the site provides

FreeCircuitSim provides a free, browser-based electronic circuit simulator and accompanying educational guides. No account, payment or subscription is required for any feature.

Educational purpose and accuracy

The simulator and all guides are provided for educational and experimental purposes. Simulation results are approximations and will differ from real-world circuit behaviour. You are responsible for verifying any design before building it in hardware. Never rely on this site alone when working with mains voltage, high current, or any circuit where failure could cause injury or damage.

Acceptable use

You may use the site for personal, educational and commercial learning purposes, including classroom teaching. You may not attempt to disrupt the service, scrape the site at volumes that degrade it for others, or republish our written guides as your own work.

The simulation engine

The simulator is built on CircuitJS1, created by Paul Falstad and ported to the browser by Iain Sharp, released under the GNU General Public License v2. That engine remains the property of its authors and is used in accordance with its licence. Our written guides, example organisation, and site design are our own work.

Your circuits

Circuits you create remain yours. They are encoded in the page URL or stored in your own browser and are not uploaded to or stored on our servers. We cannot recover circuits you lose, so export anything important.

Advertising and affiliate links

The site is supported by advertising and may contain affiliate links to component suppliers. If you buy through an affiliate link we may earn a small commission at no extra cost to you. This never affects which tools or products we recommend.

Third-party trademarks

Multisim is a trademark of National Instruments, LTspice of Analog Devices, Tinkercad of Autodesk, and CircuitSim of Elsewhere Labs, LLC. FreeCircuitSim is not affiliated with or endorsed by any of them. These names are used only to identify the products being compared.

No warranty and limitation of liability

The site is provided "as is", without warranty of any kind. We do not guarantee uninterrupted availability or that results will be error-free. To the maximum extent permitted by law, including under the Australian Consumer Law, we are not liable for any loss or damage arising from your use of the site.

Changes

We may update these terms from time to time. Changes take effect when posted on this page with a revised effective date.

Contact

Questions about these terms can be sent through our contact form.