What order are files merged in?

The order you select them in your file picker, first to last.

What if my files have different columns?

Rows are appended as-is, so mismatched files will have misaligned columns. Align the headers first — our CSV validator can spot inconsistent column counts.

Is there a file count limit?

No hard limit — merge as many as your browser's memory allows.

/ free tool

CSV Merger — Combine Multiple Files

Combine multiple CSV files into one free in your browser. Keeps one header row, appends all data — no upload, no signup.

100% free
Runs in your browser — nothing is uploaded
No signup required

Files share a header row (keep only the first)

Choose two or more CSV files to merge — or drag them here.

Monthly exports, per-region reports, chunked downloads — data often arrives as a pile of CSVs that you need as one file. Select them all here and get a single merged CSV in order.

When your files share the same header (the usual case), the merger keeps the first file's header and drops the rest, so you don't end up with header rows scattered through your data.

Example

Input

jan.csv (100 rows) + feb.csv (120 rows)

Output

merged.csv — 220 data rows under one header

Your data never leaves your device

Like everything at OpenCSV, this tool processes files locally in your browser. There is no upload, no server-side processing, and no copy of your data anywhere — which makes it safe for customer lists, financial exports, and other sensitive files.

/ frequently asked

Frequently Asked Questions

The order you select them in your file picker, first to last.

/ more free tools

Keep working with your CSV

Need to view or edit the file first?

OpenCSV is the fastest CSV editor on the web — open, fix, and save any CSV in seconds. $1 lifetime access.

Try OpenCSV free