CSV Formatter & Converter

Clean CSV or TSV data, remove duplicates, and convert it to JSON in your browser

Files are processed locally and never uploaded. UTF-8 and Shift_JIS input files are supported.

CSV / TSV Input

Open File

Input delimiter

Output format

Trim whitespace in cellsRemove empty rowsRemove duplicate rows (excluding header)

Result

What this tool does

Preview CSV and TSV data as a table, remove empty or duplicate rows, change delimiters, and convert the result to JSON in your browser. Properly quoted commas and multiline fields are supported.

Common use cases

Clean empty and duplicate rows from exports created by spreadsheets or business systems.
Convert between CSV and TSV to match an import format.
Use the first row as property names and turn tabular data into JSON.

How to use it

Paste CSV or TSV text, or choose a data file.
Select the delimiter and options such as removing empty or duplicate rows.
Check the preview, then copy or download the result as CSV, TSV, or JSON.

Input and output example

Input: name,city "Yamada, Taro",Tokyo "Yamada, Taro",Tokyo

Output: CSV, TSV, or JSON with one duplicate row removed while keeping “Yamada, Taro” in one cell

Important notes

JSON conversion normally uses the first row as property names.
Duplicate removal compares the entire row and does not normalize spelling differences.
If a file is garbled, convert it to UTF-8 with the Text Encoding Converter first.

Frequently asked questions

Can it parse commas and line breaks inside a cell?: Yes. Commas and multiline values are supported when the field is correctly enclosed in double quotes.
Is the CSV file uploaded to a server?: No. Reading, cleaning, conversion, and download all happen in your browser.