: If your computer asks if you're sure you want to change the extension, click Yes .

The quick way to 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.

: Right-click the new ZIP file and change the name from project.zip to project.sb3 .

While manual renaming is the standard, several modern tools offer more advanced ways to package or modify these files:

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 those files and compress them into a new ZIP archive.

: Go to the Scratch Editor , click File > Load from your computer , and select your new .sb3 file. 2. Modern Conversion Tools (Updated 2026)