Overview

PhET is a collection of interactive science and mathematics simulations built around visual exploration. It is best suited to students and teachers who want to investigate concepts through virtual experiments, though users who need a formal course or a fully supported Android browser experience should look elsewhere.

Key features

PhET’s simulations use interaction, visual models, multiple representations and real-world connections to make scientific ideas explorable rather than purely explanatory. That approach suits classroom demonstrations and independent practice, while flexible design principles give teachers room to use simulations in different lesson contexts. Guided lessons and virtual experiments extend the collection beyond simple visualizations.

PhET says its simulations are evaluated for educational effectiveness through student interviews and classroom observation. That gives educators a basis for using them as learning materials, rather than treating them only as illustrations. All simulations are open source, which supports reuse and adaptation; commercial use, however, requires a license from the University of Colorado Boulder.

Most simulations use HTML5 and can run online or be downloaded, but some older titles rely on Java or Flash. The Windows and macOS desktop app includes HTML5 and Java simulations and translations for offline access. Android and iOS apps include HTML5 simulations and translations, and automatically download new HTML5 simulations. The mobile apps therefore provide a practical offline option, but their stated coverage does not extend to the legacy Java or Flash simulations.

PhET states that it collects no personally identifiable information when simulations are run on its website, in apps, embedded elsewhere or from downloads. It also says it uses no advertisements or ad tracking, and serves communications over HTTPS by default. Educators can create accounts using Clever, and schools can deploy apps through Google Admin Console and Apple School Manager or Apple Business Manager.

Pricing

The Free simulations plan costs 0.00 USD per free and is free to all students and teachers. It includes access online or by download, and the simulations are open source. For learners and educators using PhET for noncommercial teaching or study, that makes the free plan the central offering rather than a limited preview.

The overall pricing model is freemium, with paid access from $0.99. Commercial use is not covered by the free educational access: it requires a commercial license from the University of Colorado Boulder. No seat limits, usage quotas, or renewal terms are stated for the free plan.

Platforms

PhET supports web, Windows, macOS, iOS and Android, as well as select Chromebooks. Windows and macOS users can use the desktop app for offline HTML5 and Java simulations; the iOS and Android apps offer offline HTML5 access and automatic downloads of new HTML5 simulations. Android is not officially supported for browser-based HTML5 simulations, so Android users should use the app. Linux is also not officially supported, which makes PhET a less certain choice for Linux-dependent classrooms.

Who it's for

PhET is designed primarily for preschool, K–12 and university learners, with particular strength in K–12 science. Teachers can use simulations for guided lessons, visual demonstrations and virtual experiments, while students can explore concepts online or offline. It is less appropriate for commercial users without a license or for organizations seeking a supported Linux or Android-browser deployment.

Pros and cons

Pros: Free access for students and teachers includes online and downloadable simulations, making it suitable for classroom and individual use without a subscription barrier.
Pros: Offline apps cover Windows and macOS desktop use and HTML5 simulations on iOS and Android, useful where connectivity is unreliable.
Pros: Open-source simulations, no ads or ad tracking, and PhET’s stated privacy protections support classroom adoption.
Cons: Android browser-based HTML5 simulations and Linux are not officially supported, narrowing dependable platform options.
Cons: The mobile apps’ stated offline coverage is HTML5 only, while some older simulations use Java or Flash.
Cons: Commercial users need a separate license, so free educational access does not fit every organization.

Alternatives

For a wider range of science-learning options, browse Science Learning Software; for chemistry-focused tools, see Chemistry Simulation Software.

Beyond Labz is worth considering for chemistry learners who want an instructor tier that is always free and can teach, preview and build assignments, with a separate one-time Chemistry option. PraxiLabs may suit learners seeking a time-limited trial of three simulations with real-time guidance and English or Arabic interface options. For schools and districts that want a limited free account alongside paid packages, ExploreLearning Gizmos offers a limited collection at no cost and customized paid subscriptions.

LabXchange is another free educational resource platform, supported by grant funding. Concord Consortium STEM Learning Tools may suit users seeking free, noncommercial STEM resources. Schools looking for tiered plans based on student numbers and district-wide or multi-year options can consider Inq-ITS. Teachers wanting classroom gameplay and assignment limits should compare Legends of Learning, while MEL Science is an alternative with a subscription model.

Verdict

Choose PhET if you are a student or teacher looking for free, open-source science and mathematics simulations that can support visual exploration online or offline. Its classroom-oriented design, broad age range and offline apps make it a strong learning resource. Look elsewhere if you need officially supported Linux or Android browser access, or if you plan commercial use and do not want to secure a separate license.

	MoluCAD	PhET Interactive Simulations
Free plan	Yes	Yes
Free trial	No	No
Paid from	Free	Free
Open source	No	No
Platforms	Windows	Web, Windows, macOS, iOS, Android
Free plan	Yes	Yes
Molecular modeling	Yes	—
Delivery	desktop	—

MoluCAD vs PhET Interactive Simulations

MoluCAD

PhET Interactive Simulations