What if my files have different column orders?

Columns are matched by header name, not position. A file with columns A, B, C and another with C, A, B will still merge correctly.

Is my data uploaded to a server?

No. Everything runs locally in your browser using JavaScript. Your files never leave your device.

Are duplicate rows removed automatically?

No — the merger keeps all rows including duplicates. Use the Data Deduplicator tool afterwards if needed.

Can I merge more than 2 files?

Yes — add as many CSV files as you like. All are merged into a single output file.

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CSV Merger

Merge multiple CSV files into one, aligning columns automatically by header name. Missing columns are left blank. Download the merged CSV. Free.

📊 Data & CSV Tools Free Browser-based

Tool

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Drop CSV files here or browse

Columns are aligned automatically by header name

How Column Alignment Works

Each CSV's headers are collected into a unified set of all unique column names. Rows from each file are mapped to those columns — if a file doesn't have a particular column, that cell is left empty. This ensures all data aligns correctly regardless of column order.

Use Cases

Combine monthly export files into a yearly report, merge data from multiple sources with slightly different schemas, or concatenate split data files back together.

CSV Merger

How Column Alignment Works

Use Cases

Frequently Asked Questions