> For the complete documentation index, see [llms.txt](https://docs.mapbox.com/help/ja/llms.txt)

# Source limits in Mapbox Studio styles

[Styles](https://docs.mapbox.com/help/ja/glossary/style/) made with the Mapbox Studio style editor or uploaded to your Mapbox account have a limit of 15 [sources](https://docs.mapbox.com/help/ja/glossary/source/). If you try to add more than 15 sources to your style, you receive the error message `Failed to update style`.

## Check number of sources used

To check the number of sources used in your style, open the style in the Mapbox Style Editor, click the ** Settings** option in the top toolbar, and scroll to the **Layer overview** section.

Your browser doesn't support HTML5 video. Open [link to the video](https://docs.mapbox.com/help/ja/help/ja/assets/medias/reduce-tileset-sources-style-reference-899ba2b546d789fe540dd06372c3dd04.mp4).

## Reduce the number of sources

There are several strategies to reduce the number of sources in your style.

### Combine sources

The most effective way to reduce the number of sources you're using in a style is to combine data from multiple data files or tilesets into a single tileset. You can do this in several ways:

-   **Data Workbench**: Create a multi-layer tileset with the Data Workbench. Drag multiple files into the Data Workbench to create a multi-layer tileset. Note that dragging multiple files into Studio will create a multi-layer tileset.
-   **GIS application**: Use a tool outside of Mapbox, such as QGIS or ArcGIS, to merge your geospatial data before you upload it to Mapbox.
-   **Tippecanoe**: Use the open-source command line tool, [Tippecanoe](https://github.com/mapbox/tippecanoe#tippecanoe), to add multiple data files to a single tileset source, export to MBTiles, and upload them all at once to Mapbox.

### Remove an unused source

A source that is no longer needed can be removed from the style by deleting all layers using that source. To delete a layer dependent on a particular source, select the layer in the **Layers** panel and click the **Delete** button at the top of the panel. Note that not all layers can be deleted.