Free online data tools
Combine Data from Multiple Files into One
Stacking twelve monthly exports into one sheet by hand is slow and easy to get wrong. Load every file at once and this tool appends them into a single CSV, matching columns by name. It works across separate CSV files, separate workbooks, or every sheet inside one workbook.
Load your data
Choose your files, then select Load Data to get started.
Your files are processed locally in this tab.
Select one or more files.
Choose your options
Setting up…
Your file is processed inside this browser tab and is never uploaded.
Frequently asked questions
Do the files need identical columns?
No. Columns are matched by name. A column missing from one file is filled with blanks for those rows, so nothing is silently dropped.
How many files can I combine at once?
As many as you can select in one go. Everything runs in your browser, so the limit is your own computer, not an upload quota.
Can I combine only some sheets of a workbook?
Yes. Choose "All Excel Sheets" and type a piece of the sheet name, for example "Sale". Only sheets whose name contains that text are combined.
Other free tools
- Split Data — Split one file into separate files or Excel sheets based on a column value.
- Merge Data — Merge or join a dataset from two different files on a shared column.
- Compare Data — Compare data from two different files and see exactly what changed.
- Change File Format — Convert data between csv, xlsx, xls, json and html.