To convert a ZIP file to an SB3 (Scratch 3.0) project, you generally follow a manual renaming process. An .sb3 file is essentially a ZIP archive containing a project.json file and various assets (images and sounds). Manual Conversion Steps
Prepare your files: Ensure your ZIP archive contains a file named project.json at its root, along with any necessary assets (like .svg, .png, or .wav files).
Check file extensions: If you cannot see file extensions (like .zip), enable them in your file explorer:
Windows: Open File Explorer, go to the View tab, and check File name extensions. Rename the file: Right-click your .zip file and select Rename. Change the extension from .zip to .sb3.
A warning will appear asking if you are sure you want to change the extension; click Yes or Use .sb3.
Test in Scratch: Go to the Scratch Editor, click File > Load from your computer, and select your new .sb3 file to ensure it opens correctly. Why this works
Scratch 3.0 projects use the ZIP format to bundle all project data together. By renaming the extension, you are simply telling the Scratch editor to treat that specific archive as a project file.
If you are trying to package a Scratch project into an executable or different format, tools like the TurboWarp Packager are often used to handle the conversion in the opposite direction (SB3 to ZIP/EXE). convert zip to sb3 updated
If you run into an error when loading, it usually means the project.json file is missing or located inside a subfolder within the ZIP rather than at the root level.
Do you have the project.json file ready, or are you trying to convert a specific type of file (like an old .sb2 or .sprite3) into a ZIP first?
Convert SCRATCH to .EXE! | .SB3 to .EXE | Just Finished Coding!
The quick way to convert ZIP to SB3 is simply to rename the file extension from .zip to .sb3. This works because an SB3 file is essentially a renamed ZIP archive containing a project.json file and all associated media assets.
Below is the updated guide for 2026 on how to handle these conversions manually and with modern tools. 1. The Manual "Rename" Method
If you have a collection of Scratch assets (like sprites, sounds, and a project.json file) inside a ZIP folder and want to turn it back into a playable Scratch project, follow these steps:
Select All Files: Open your ZIP folder and ensure the project.json file and all media assets (PNG, SVG, WAV, etc.) are at the root level of the archive. To convert a ZIP file to an SB3 (Scratch 3
Compress: Select all those files and compress them into a new ZIP archive.
Rename Extension: Right-click the new ZIP file and change the name from project.zip to project.sb3.
Confirm: If your computer asks if you're sure you want to change the extension, click Yes.
Load in Scratch: Go to the Scratch Editor, click File > Load from your computer, and select your new .sb3 file. 2. Modern Conversion Tools (Updated 2026)
While manual renaming is the standard, several modern tools offer more advanced ways to package or modify these files:
For non-technical users or batch operations, web tools are excellent. However, many old converters are now defunct or insecure. Here are the three verified online tools that convert ZIP to SB3 as of 2025:
To understand why one would convert a ZIP to an SB3, one must first understand what an SB3 file actually is. Unlike the proprietary binary formats of old software, the .sb3 format is remarkably transparent. It is, fundamentally, a ZIP archive. Check file extensions : If you cannot see
When a Scratch project is saved, the platform takes the project’s logic (stored in a JSON file named project.json) and bundles it alongside all the assets—costumes, backdrops, and sounds. This collection is then zipped up and stamped with the .sb3 extension. This design choice was a significant update from the previous Scratch 2.0 (.sb2) format, moving away from a binary structure to a web-friendly, standard-compliant archive.
This transparency allows for "backdoor" editing. If a user takes an existing .sb3 file and renames it to .zip, they can peek inside the guts of their project. Conversely, if a user has a folder full of assets and a project.json file, they can compress them into a ZIP, rename the extension to .sb3, and voila—they have created a runnable Scratch program without ever opening the Scratch editor.
While this trick has existed since the launch of Scratch 3.0 in 2019, the context of this conversion has been updated significantly in recent years. As the Scratch ecosystem has matured, the utility of the ZIP-to-SB3 pipeline has expanded beyond simple file recovery.
1. The Rise of External Editors and Turbowarp
The most pressing reason for this conversion today is the proliferation of external tools and mods. Advanced users often edit the project.json file manually to utilize features the standard Scratch editor doesn't support—such as creating custom block shapes, implementing complex list manipulation, or utilizing the "compiler" speeds found in mods like TurboWarp.
In these scenarios, the workflow is reversed. A user exports a project, edits the code in a text editor, compresses the files back into a ZIP, and converts it to SB3 to test their "hacked" creation. This process bridges the gap between the visual interface of Scratch and the raw power of text-based coding.
2. Migration and Legacy Support
With the discontinuation of Flash and the complete migration to HTML5, the Scratch team has updated how the platform handles data. While .sb2 files are still importable, the standard is .sb3. For archivists and developers creating tools to migrate content from other platforms (like Unity or Stencyl) into Scratch, generating a ZIP and converting it to SB3 is the only programmatic way to inject assets into the ecosystem without manually uploading them one by one.
