Combine several CSV or Excel files into one, matching columns by name.
About Merge CSV Files
Monthly exports, one file per store, one report per region: sooner or later you have a folder of CSV files that should be a single table. Copying and pasting them in Excel is slow and breaks as soon as one file has its columns in a different order or an extra column. This tool merges any number of CSV and Excel files into one, and by default it lines up the columns by their header name, so "Email" in one file and "email" in another end up in the same column.
Columns that exist in only some files are kept and left empty where they are missing, and you get a warning listing them. You can add a column with the name of the file each row came from, remove duplicate rows across files, and download the result as CSV or as an Excel workbook. All files are read in your browser; nothing is uploaded.
How to use Merge CSV Files step by step
Select or drag all the CSV, TSV, TXT or Excel files at once onto the upload area. You can add more files later with "Add files".
Check the list: each file shows its number of rows and columns. Remove any file you added by mistake with the X.
Keep "Match columns by header name" if the files have headers. Choose "Append rows as they are" only for files without a header or with an identical layout.
Optionally tick "Add a column with the source file name" and "Remove duplicate rows after merging".
Review the preview and the row count, choose the delimiter and click "Download merged CSV" or "Download Excel".
100% free and online: no payments, no software or extensions to install.
Privacy-first: processing happens in your browser, your data never leaves your device.
No sign-up: paste your data and get the result in one click.
Fast and reliable: handle small or large files in seconds, ready for Excel and other tools.
Common use cases
Combine twelve monthly sales exports from Shopify, Stripe or PayPal into one yearly file for analysis.
Merge contact lists from several sign-up forms or events before importing them into Mailchimp or HubSpot, removing duplicates on the way.
Join the CSV files produced by Split CSV or by a system that exports in batches back into one file.
Consolidate reports from different stores, branches or regions that share most columns but not all of them.
Stack Excel workbooks from different people into one table, keeping track of who sent each row with the source column.
Limits and tips
Header matching ignores upper and lower case and surrounding spaces, but not spelling: "E-mail" and "Email" are different columns. Rename headers in the CSV editor first if needed.
The column order of the result follows the first file, then any new columns in the order they appear in later files.
Files with different delimiters can be merged together: each file's delimiter is detected on its own, and you choose the delimiter of the output.
Only the first sheet of an Excel file is read. Use Excel to CSV first if you need another sheet.
If the merged file goes over 1,048,576 rows, the CSV download still works, but Excel will not open it entirely; split it or open it with the Large CSV Viewer.
Frequently asked questions
How do I combine multiple CSV files into one?
Select all the files at once in this tool. They are stacked into one table with the columns matched by header name, and you download the result as a single CSV or Excel file. No command line, macro or Power Query is needed.
What if the files have the columns in a different order?
With "Match columns by header name" the order does not matter: each value goes to the column with the same header. Columns missing from a file are left empty for that file's rows.
Can I merge CSV files without a header row?
Yes. Choose "Append rows as they are": rows are stacked by position. In that mode the first row of the first file is used as the header, so add a header to the first file if it has none.
How can I tell which file each row came from?
Tick "Add a column with the source file name". A source_file column is added at the end with the original file name of every row.
Are my files uploaded?
No. Files are read and merged by JavaScript in your browser. Nothing is sent to a server, so you can merge customer or financial data safely.
Related guides
Convert CSV to Excel: 5 ways, from double-click to Python — Five ways to convert a CSV file to Excel: Excel's import wizard, Google Sheets, LibreOffice, Python with pandas, and an online converter. When each one fits, and how to keep leading zeros and accents.