Check & prepare data · Supporting · Experimental helper

Merge compatible CSV files

Append the records of a second CSV to a first file with the same headers.

Private by designYour input stays on your device. Processing happens in this browser.

Your workspace

Start with a file

Choose first CSV fileCSV, TSV, or TXT · UTF-8 only · up to 10 MB. Original text and identifiers are retained; parsing happens when you run. Drop here, or use the file picker.

Choose second CSV fileCSV, TSV, or TXT · UTF-8 only · up to 10 MB. Original text and identifiers are retained; parsing happens when you run. Drop here, or use the file picker.

Paste first CSV instead (optional)

Optional alternative to a file. Editing this text removes its selected file; source text is never reformatted during loading.

CSV data

Input delimiter (optional)Leave blank to detect comma, semicolon, tab, or pipe. Otherwise enter one character.

Paste second CSV instead (optional)

Optional alternative to a file. Editing this text removes its selected file; source text is never reformatted during loading.

Second CSV data

Ctrl / ⌘ + Enter to run

Result

A clear result starts here

Run the tool to see your output here.

Try the example to explore how it works.

What to know about this tool

Headers must match exactly, including order and case. This appends rows without joining by key or removing duplicates. Up to 10 MB, 50,000 rows and 200 columns; rectangular CSV with unique nonblank headers required. CSV output has a conservative 20 MB cap.

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Merge compatible CSV files

Start with a file

A clear result starts here

Clear this workspace?

Start with a file

A clear result starts here

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