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# Upload several files or a whole folder to Mammoth

> Upload up to 1,000 files or a whole folder to Mammoth at once: each file becomes its own dataset, folders are recreated, and folder rules can route files.
>
> Applies to: Where: Data Library › New dataset › Upload › Upload folder

You can upload many files in one go: in the **Data Library**, click **New dataset**, keep **Upload** selected, then pick several files or click **Upload folder**, and click **Submit**. Each file becomes its own dataset. For a single file and the supported formats, see [Upload CSV, Excel and other files](https://mammoth.io/docs/learn/get-data-in/upload-files/).

## Upload several files at once

Select several files in the same dialog, up to 1,000 files per upload. Each file becomes its own dataset and is sent as its own upload; Mammoth sends them in groups of 50, with a 30-second pause between groups. A file Mammoth can't accept is left out, and a message names it and says it "was not added: its file type is not supported, or it is too large."

## Upload a whole folder

1. Click **New dataset**, then **Upload**.
2. Click **Upload folder** and select the folder.
3. Click **Submit**.

Each file in the folder becomes its own dataset. Mammoth recreates the folder, and any subfolders, as folders in your Data Library. Only supported file types are added, and the whole folder must be under 50 MB, because it is uploaded as a single request.

![New Dataset dialog after Upload folder, listing several date test files from a Dates folder with Submit enabled](https://mammoth.io/docs/images/20260408_152410_Upload_multiple_files_from_folder.webp)

## Upload into a folder that has automation rules

When you upload from inside a Data Library folder with folder automation rules, a **Where these files go** box under the file list shows which dataset a rule sends each group of files to.

- The first matching rule wins. A file that matches more than one rule says, for example, "Also matches Monthly sales, but Sales by region comes first."
- A file no rule takes shows **Stays here** ("No rule takes it, so it becomes its own dataset here.").
- When a rule takes any file, the box adds "Added files leave this folder once they're in their dataset."

See [Folders and folder rules](https://mammoth.io/docs/learn/organise/folders/).

## Combine many files into one dataset

| Symptom | Cause | Fix |
| --- | --- | --- |
| Several files made several datasets, but you wanted one | Each uploaded file becomes its own dataset, including files in **Upload folder** | Use **Add data** on an existing dataset to add later files to it, or set up [Data Consolidation](https://mammoth.io/docs/learn/automate/consolidate/). Make sure the files share the same columns and aren't empty. |

## Related

- [Upload CSV, Excel and other files](https://mammoth.io/docs/learn/get-data-in/upload-files/): formats, limits and upload errors.
- [Folders and folder rules](https://mammoth.io/docs/learn/organise/folders/): set up the rules that route uploaded files.
- [Add or replace data in a dataset](https://mammoth.io/docs/learn/get-data-in/add-or-replace-data/): add later files to one dataset.
- [Combine incoming data](https://mammoth.io/docs/learn/automate/consolidate/): add new files to a dataset on their own.

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Source: https://mammoth.io/docs/learn/get-data-in/upload-many-files.md · Updated: 2026-11-08