Free tool
Annotation Merger
Combine COCO, YOLO, Pascal VOC, CVAT, LabelMe, CSV, TSV, and JSONL annotation files into one clean export or ZIP in the format your next step expects.
Merge annotation files
Add annotation files or a ZIP, pick the output format, and download one merged export. Add the images too when the labels do not include image sizes, such as YOLO.
Frequently asked questions
- Which annotation formats can I merge?
- The merger detects COCO JSON, CVAT XML, Pascal VOC XML, YOLO TXT, LabelMe JSON, CSV, TSV, and JSONL. COCO, CVAT, JSONL, CSV, and TSV files can be mixed in one merge. YOLO, Pascal VOC, and LabelMe files must be merged with files of the same format.
- How do I merge multiple COCO JSON files into one?
- Select all of the COCO files, or a ZIP that contains them, and choose COCO as the output. Images and annotations from every file are combined into one COCO file, and categories with the same name become one category.
- How many files can I merge at once?
- Up to 300 files per merge, with 10 MB per file and 25 MB in total. You can run up to 10 merges every 5 minutes.
- Are my files uploaded?
- The files you select are sent to LabelOp servers for processing, and the result comes back as a download. You do not need an account.