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# Import some or all sheets from an Excel workbook

> Choose which sheets of an Excel workbook become Mammoth datasets, tell Mammoth how to read a sheet, combine matching sheets, and replace the workbook later.
>
> Applies to: Where: Data Library › dataset panel › Extract sheets

When you upload an Excel workbook with several sheets, Mammoth lets you choose which sheets become datasets and how each is read. The dataset's panel in the **Data Library** shows "This file has multiple sheets to be extracted." with an **Extract sheets** button. For other files that read wrongly, see [Fix how Mammoth reads a messy file](https://mammoth.io/docs/learn/get-data-in/how-mammoth-reads-files/).

## Pick, read and save the sheets

1. Click **Extract sheets**. Under **Sheets**, tick the sheets to include. Mammoth reads each sheet when the window opens and shows how many tables it found (for example, "Reads as 2 tables").
2. Click a sheet to see its **Source** next to the dataset it makes. A sheet is **Read automatically** by default.
3. To change how a sheet is read, click **Say how to read** and the sheet name (for example, **Say how to read Q1**). Describe it, for example "row 3 is the header" or "rows 1 to 3 are a table", and click **Run this instruction**. **Back to automatic read** undoes your read.
4. When tables share the same columns, Mammoth groups them: "Combining adds a Source column to tell them apart." Tick two or more and click **Combine** (for example, **Combine 3 datasets**), or keep them **Separate**.
5. Click **Looks right**. The save step lists the **Datasets to create** with their **Cols** and **Rows**.
6. Untick any you don't want, rename them, and click **Save** (for example, **Save 3 datasets**).

One recipe produces all the datasets, and every run updates them together.

## Replace the workbook or add sheets to a watched folder

- **Replace this file:** drop or choose another workbook (.xlsx, .xlsm, .xls or .csv) to rebuild the recipe from it. If you already edited reads, renamed sheets or changed which datasets to save, Mammoth warns **Replacing loses your edits**, with **Keep this file** and **Replace anyway**.
- When a later file has different sheets, the window says "This file has different sheets from the last one." and names the sheets that are new or gone.
- When the workbook was uploaded to a watched folder, the save button reads, for example, **Add 3 sheets to Monthly sales**: "They go in as new batches, the way any file added to this folder does."

## Related

- [Fix how Mammoth reads a messy file](https://mammoth.io/docs/learn/get-data-in/how-mammoth-reads-files/): recipes, dates and delimiters.
- [Upload CSV, Excel and other files](https://mammoth.io/docs/learn/get-data-in/upload-files/): upload the workbook.
- [Prepare files for a clean upload](https://mammoth.io/docs/learn/get-data-in/prepare-files-for-upload/): what an Excel import keeps.
- [Batches: see and fix what arrived](https://mammoth.io/docs/learn/get-data-in/batches/): sheets added to a watched folder arrive as batches.

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Source: https://mammoth.io/docs/learn/get-data-in/extract-excel-sheets.md · Updated: 2026-11-08