How to merge Excel or CSV files
- Drop your files on the page, choose them, or choose a whole folder. A workbook with several sheets shows each sheet on its own line; untick any you don't want.
- Choose One sheet to stack every row into a single table, or One tab per file to collect the files, unchanged, into one workbook.
- Check the preview and the column map underneath it. A column that only some files have is flagged, so a surprise shows up before you download, not after.
- Download. Excel files keep dates and number formats; CSV is plain text that any program can open.
How columns are matched
Columns are matched by their names, not their position. Capital letters, spaces and punctuation are ignored, so E-mail, email and EMAIL all land in one column. The order of columns in each file doesn't matter.
A column that only some files have is still kept. Rows from the other files are left blank in it. Names that use different words are not guessed at: Zip and Postal code stay separate, because a wrong guess would mix up your data silently. Rename one of them in its file so they match, then add the file again.
If your files have no header row, untick First row has column names. Columns are then lined up by position, A with A and B with B, and named Column A, Column B and so on.
A worked example
Two sign-up lists from different places. The second one lists email first, spells it E-mail, has no phone column and adds a sign-up date.
spring-fair-signups.csv
| Row | A | B | C |
|---|---|---|---|
| 1 | Name | Phone | |
| 2 | Dana Whitfield | dana@example.com | (614) 555-0142 |
| 3 | Marcus Bell | marcus@example.com | (512) 555-0178 |
newsletter-export.csv
| Row | A | B | C |
|---|---|---|---|
| 1 | name | Signed up | |
| 2 | grace@example.com | Grace Liu | 3/2/2026 |
| 3 | andre@example.com | Andre Wallace | 3/9/2026 |
Merged into one sheet with a source column, the names and emails line up, Phone is blank for the newsletter rows, and Signed up is blank for the fair rows:
merged.xlsx
| Row | A | B | C | D | E |
|---|---|---|---|---|---|
| 1 | Source file | Name | Phone | Signed up | |
| 2 | spring-fair-signups.csv | Dana Whitfield | dana@example.com | (614) 555-0142 | |
| 3 | spring-fair-signups.csv | Marcus Bell | marcus@example.com | (512) 555-0178 | |
| 4 | newsletter-export.csv | Grace Liu | grace@example.com | 3/2/2026 | |
| 5 | newsletter-export.csv | Andre Wallace | andre@example.com | 3/9/2026 |
The sample files in the tool above are a slightly bigger version of this, including a person who signed up twice. Merging keeps both rows; removing duplicates by email afterwards leaves one.
One sheet or one tab per file?
One sheet is for working with the data: sorting, filtering, a pivot table, a mail merge or an upload to another system. It needs the files to describe the same kind of thing, such as customers or transactions.
One tab per file is for keeping things together without changing them: twelve monthly reports in one workbook, or a set of files to send as a single attachment. Nothing is matched or reordered; each file is copied onto its own tab, named after the file.
Before you merge
- Title rows above the table. Exports often start with a report title or a date range. Delete those rows so the column names are in the first row, or they'll be read as data.
- Total rows at the bottom. A totals line is merged like any other row. Remove it first, then total the merged file.
- Leading zeros. ZIP codes such as 02134 and IDs such as 00981 are kept as text in the Excel file, so the zeros survive.
- Repeated people or orders. If the same customer appears in two files, both rows are kept. Remove rows that repeat exactly only catches rows that match in every column.
Merging in Excel itself
For two or three small files, copying and pasting works if the columns are in the same order. Check the order first: pasting a file whose columns are shuffled puts emails under the Name heading without any warning.
Excel for Windows (2016 and later, including Microsoft 365) can also combine a folder of files with Power Query: Data > Get Data > From File > From Folder, pick the folder, then choose Combine & Load. It takes more steps the first time, but the query can be refreshed when new files arrive, which suits a job you repeat inside Excel.
Merging is not the same as matching. If you want to add a column from one list to another by a shared value, like putting phone numbers next to emails, that's a lookup (XLOOKUP or VLOOKUP in Excel), not a merge. This tool stacks rows.