Need to merge multiple CSV files into one? Our free online CSV Merger tool lets you combine CSV files instantly — right in your browser. No uploads to any server, no software to install, no sign-up required. Your data never leaves your computer.
Drag & drop CSV files here, or click to browse
How to Use the CSV Merger Tool
Step 1: Add Your CSV Files
Drag and drop your CSV files onto the upload area, or click it to browse your computer. You can add as many files as you need — they’ll all appear in the file list with their row counts.
Step 2: Choose Your Output Format
You have two download options:
- Merged CSV — Combines all rows from every file into a single CSV file, one after another. Perfect when all your files share the same columns and you want one flat file.
- Excel (Separate Tabs) — Creates an Excel workbook (.xlsx) where each original CSV file becomes its own sheet tab. Great for keeping your data organized while having everything in one workbook.
Step 3: Preview Before Downloading
Click Preview to see the combined result before downloading. Use the tabs at the top of the preview to switch between the merged view and individual file views.
Managing Your Files
- Click the ✕ button next to any file to remove it
- Click Clear All to start over
- Add more files at any time — just drag and drop again
Why Use Our CSV Merge Tool?
- 100% Private — Your files are processed entirely in your browser. Nothing is uploaded to any server. Your data stays on your computer.
- No Software Required — Works in any modern browser on Windows, Mac, Linux, or mobile. No Python scripts, no command line, no Excel macros.
- No File Size Limits — Handle large CSV files without the restrictions of other online tools.
- Instant Results — Merge hundreds of thousands of rows in seconds.
- Multiple Output Formats — Download as a single merged CSV or an Excel workbook with separate tabs for each file.
- Free Forever — No sign-up, no trial, no premium tier. Just a tool that works.
Common Uses for CSV Merging
- Combining monthly reports — Merge January through December CSVs into one annual spreadsheet
- Consolidating data exports — Combine CSV exports from different systems or departments
- Preparing data for analysis — Stitch together datasets before importing into Power BI, Google Sheets, or Excel
- E-commerce inventory — Merge product catalogs from multiple suppliers
- CRM data cleanup — Combine contact lists from multiple sources
Frequently Asked Questions
Do my files get uploaded anywhere?
No. Everything runs locally in your browser using JavaScript. Your CSV data never touches our servers or any third-party service.
Can I merge CSV files with different columns?
The tool works best when all files share the same column structure. If files have different numbers of columns, it will pad shorter rows with empty cells to match the first file’s column count.
Is there a limit on file size or number of files?
There are no artificial limits. The only constraint is your browser’s available memory. In practice, you can easily merge millions of rows.
Can I combine CSV files into separate Excel tabs?
Yes! Click the green “Excel (Separate Tabs)” button to download an .xlsx file where each CSV becomes its own named sheet.
Does it work on Mac, Windows, and mobile?
Yes — it works in any modern web browser on any operating system, including phones and tablets.
