Convert SB2 to SB3

A Scratch 2 project saved as .sb2 must be migrated when it needs editing or sharing in the current Scratch 3 web editor or desktop app. Saving the imported project as .sb3 also preserves a usable copy for current Scratch users while retaining the original archive.

What the SB2 format is

.sb2 is the project format used by Scratch 2, the block-based programming environment used in schools, tutorials, and personal projects. Scratch 2 Online and the Scratch 2 Offline Editor create SB2 files with File → Download to your computer.

An SB2 file is a packaged archive containing the project description, block scripts, sprites, costumes, sounds, stage settings, variables, lists, broadcasts, custom blocks, and project metadata. Older classroom projects and Scratch files exported before Scratch 3 commonly use this extension.

What the SB3 format is

.sb3 is the native project format for Scratch 3, used by the Scratch website and Scratch 3 Desktop. It packages the project description and media assets in the format expected by the Scratch 3 editor and supports its current block set and extensions.

SB3 is the appropriate format for opening, editing, and sharing a migrated project through Scratch 3. Scratch 3 saves the result as a new SB3 file; it does not rewrite the original SB2 file.

How to convert SB2 to SB3

1. Open the official Scratch 3 editor at https://scratch.mit.edu/projects/editor/, or install Scratch 3 Desktop from the official Scratch website.
2. In the editor, select File → Load from your computer.
3. Select the source .sb2 file. Scratch 3 imports the archive and translates its project data into the Scratch 3 format.
4. Run the project and inspect the stage, sprites, scripts, variables, lists, broadcasts, custom blocks, costumes, and sounds.
5. Select File → Save to your computer. Scratch downloads the converted project as an .sb3 file.

The Scratch 3 web editor is the reputable online conversion option, and Scratch 3 Desktop performs the same task locally. A separate online converter is normally unnecessary; do not upload private, unpublished, or student projects to an unverified service.

Compatibility and limitations

Most standard Scratch 2 content imports: ordinary scripts, sprites, costumes, sounds, variables, lists, broadcasts, and custom blocks. Scratch 3 may change or omit behavior for obsolete blocks, Scratch 2 extensions, hardware integrations, browser-dependent features, or projects created with modified Scratch distributions. Enable the corresponding Scratch 3 extension or revise affected scripts when the importer cannot provide an equivalent.

Test timing, input handling, video sensing, sound playback, pen features, and imported graphics after conversion. Differences between Scratch 2 and Scratch 3 runtimes can alter block behavior even when the scripts appear intact.

Cloud-variable values are stored on Scratch’s servers rather than in the downloaded project, so converting the file does not transfer those saved values. The project may retain cloud-variable declarations, but its server data depends on the Scratch account and project state.

Keep the original .sb2 file. Conversion creates a new package and is not a byte-for-byte or fully reversible transformation.