Merge CSV
Merge CSV files into one — columns matched by header, header kept once, duplicates removed, saved as CSV or Excel.
- Files never leave your device
- 100% free
- No sign-up
- No watermark
- Works offline after first load
or drag & drop the CSV files to merge here
How to merge CSV files
- Select or drop the CSV, TSV or TXT files to merge and put them in order with the arrows. Each file’s separator and encoding are detected.
- Choose how to line up the columns (by header name or by position), whether to add a column with the file name, and whether to remove repeated rows.
- Pick CSV or Excel and click Merge CSV files to download one combined file.
About Merge CSV
Combine many CSV files into one. Each file’s separator and text encoding are detected, the header is kept once, and columns are lined up by their header names — so exports with columns in a different order, or with extra columns, still merge correctly.
Add a column with the name of the file each row came from, remove rows that appear more than once, and save as a CSV with the separator and encoding you need or as an Excel workbook with a filterable header. Nothing is uploaded.
Good for
- Combining daily or monthly CSV exports
- Joining order or contact lists from several systems
- Building one dataset from many CSV downloads
Tip: Files without a header row? Untick “Files have a header row” and line columns up by position.
Frequently asked questions
What if my CSV files have their columns in a different order?
Choose to line up columns by header name: each value goes under the right header whatever its position, and columns that only some files have are added at the end. Choose by position for files without headers.
Is the header repeated?
No. With “Files have a header row” the header appears once at the top and the header rows of the other files are left out.
Can files with different separators be merged?
Yes. The separator (comma, semicolon, tab or pipe) and the encoding of each file are detected separately, and the result uses the separator you choose.
Can I see which file each row came from?
Yes. Tick “Add a column with the file name”.
Can duplicate rows be removed?
Yes. Tick “Remove repeated rows” and rows that are exactly the same are kept once. For duplicates by certain columns only, use Remove Excel Duplicates.
Can I get an Excel file instead?
Yes. Save as .xlsx to get a workbook with a bold, frozen header and filter buttons.
Are my files uploaded?
No. Merging happens entirely in your browser — your data never leaves your device.