CSV Merger

Merge multiple CSV files into one. Combine vertically (append rows) or horizontally (add columns). Free, secure, browser-based.

How to Merge CSV Files Online

  1. 1

    Upload Your CSV Files

    Drag and drop two or more CSV files into the upload area, or click to browse your computer. You can select multiple files at once. The tool reads them instantly in your browser without uploading anything to a server.
  2. 2

    Choose Merge Mode and Delimiter

    Select vertical merge to stack rows from all files into one long dataset, or horizontal merge to place columns side by side. Pick the delimiter that matches your files: comma, semicolon, or tab.
  3. 3

    Reorder Files and Configure Headers

    Use the arrow buttons to arrange files in the order you want them merged. Enable the skip-headers option in vertical mode to prevent duplicate header rows when combining files that share the same column structure.
  4. 4

    Preview and Download the Merged File

    Review the merged output in the live preview table. Check that columns align correctly and rows appear in the expected order. When everything looks right, click Download Merged CSV to save the combined file to your device.

Common Use Cases

1

Combining Monthly Reports

Merge monthly sales, analytics, or financial CSV exports into a single annual dataset. Vertical merge stacks each month's rows together while preserving column structure, giving you one file ready for analysis.
2

Consolidating Data Exports

When you export data from multiple platforms or databases, each source produces its own CSV. Use the merger to combine CRM contacts, email lists, or inventory records into one unified file for import.
3

Joining Related Datasets by Column

Use horizontal merge to combine related datasets that share the same row order. Add demographic columns alongside survey responses, or attach calculated fields from a separate sheet to your main data table.
4

Preparing Data for Analysis Tools

Data analysis tools like Excel, Google Sheets, or Python pandas work best with a single input file. Merge scattered CSV fragments into one clean dataset before loading it into your analysis workflow.

Why Use CSV Merger?

Combining multiple CSV files manually is tedious and error-prone. Our CSV Merger lets you quickly combine files vertically (stacking rows) or horizontally (adding columns side by side). Perfect for combining monthly reports, merging data exports, or consolidating datasets.

CSV Merger is a free browser-based tool that combines multiple CSV files into a single output file. Whether you need to stack rows from monthly exports or join columns from related datasets, this tool handles both vertical and horizontal merging with full control over delimiters and header handling. All processing runs locally in your browser, so your data never leaves your device.

Vertical merging appends the rows of each file in sequence, which is ideal for combining time-series data, log files, or any exports that share the same column structure. Horizontal merging places columns side by side, which works well when you have related data split across separate files. You can reorder files before merging, choose between comma, semicolon, or tab delimiters, and preview the combined output before downloading. For further data preparation, use the CSV Column Extractor to select only the columns you need, or convert the result to JSON with the CSV to JSON Converter.

After merging, you can inspect the output in the CSV Viewer, convert it to Excel format with CSV to Excel, or open it directly in the Spreadsheet Editor for further editing. If you need to compare two versions of a file before and after merging, the Diff Checker highlights every difference line by line.

How It Compares

Desktop spreadsheet applications like Microsoft Excel and Google Sheets can combine CSV files, but they require you to open each file individually, copy-paste data, and manually align columns. Dedicated command-line tools such as cat or csvkit are powerful but require technical knowledge and a local installation. Online alternatives often require account creation, impose file size limits, or upload your data to remote servers.

FindUtils CSV Merger runs entirely in your browser with no installation, no signup, and no file uploads. It supports both vertical and horizontal merge modes, lets you pick your delimiter, and gives you a live preview of the merged output. There are no usage limits, no ads, and no data leaves your device. For most CSV merging tasks, this free tool replaces both manual spreadsheet work and command-line scripting.

Tips for Better CSV Merging

1
Make sure all files use the same delimiter before merging. Mixing commas and semicolons will produce malformed output.
2
For vertical merges, ensure all files share the same column order. The tool merges by position, not by column name.
3
Enable the skip-headers option when stacking files that each contain a header row to avoid repeated headers in the output.
4
Preview the merged result before downloading to catch column misalignment or unexpected blank cells early.
5
If your merged file needs further cleanup, open it in the CSV Viewer or Spreadsheet Editor to sort, filter, or remove unwanted rows.

Frequently Asked Questions

1

What's the difference between vertical and horizontal merge?

Vertical merge appends rows from each file (like stacking spreadsheets). Horizontal merge adds columns side by side (like joining tables).
2

What happens to headers when merging?

In vertical mode, you can choose to skip headers from the 2nd file onwards to avoid duplicate header rows. In horizontal mode, all headers are preserved.
3

Can I reorder the files before merging?

Yes! Use the up/down arrows to change the order of files. The merged output will follow your specified order.
4

Is there a limit on file count or size?

No hard limit, but since processing happens in your browser, very large files may be slow. Most devices handle dozens of files smoothly.
5

Is my data secure?

Yes, all processing happens locally in your browser. Your files are never uploaded to any server.

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