CSV · JSON · CLEANUP / FREE TOOL

Merge CSV Files

Combine multiple CSV files with matching column headers.

Your workspace

Free · local processing

Choose task Choose local file (.csv, .tsv, .json, .txt)

Max 3MB/file, up to 15 files. Inputs are not uploaded to a processing server.

Input text (CSV or JSON)

Delimiter

Deduplicate by column (optional)

Select multiple CSV files with identical headers. Rows are appended in the order selected.

CSV-to-JSON preserves leading-zero identifiers as strings. CSV exports neutralize potentially dangerous spreadsheet formulas.

Can I merge different column names?

No. To prevent accidental corruption, mismatching headers stop the merge.