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CSV to JSON Converter

Convert CSV to JSON in your browser. The header row becomes the keys, quoted fields survive, and no types are guessed or invented.

Paste CSV

Options

JSON result

Paste CSV, or choose a file, then convert.

The JSON appears here after conversion.

Limit for uploaded files: 25 MB. Pasted text is not truncated by the tool — your browser’s memory is the ceiling.

Your file is never sent to a server. It is read and processed by your own browser, and the results are not stored.

How to use it

  1. Paste CSV into the input box, or choose a .csv file.
  2. Pick the indentation and confirm that the first row is the header.
  3. Convert, then copy the JSON or download it as a file.

Limits worth knowing

  • Every output value is a string; type coercion is deliberately not performed.
  • Rows above 200,000 and files above 25 MB are refused to keep the tab responsive.
  • Multi-document output is not produced; the result is one JSON array of objects.
  • The output is re-serialised, so insignificant whitespace in quoted fields is preserved only as far as CSV does.

When CSV hides a problem

A CSV that looks fine in a spreadsheet can be ambiguous elsewhere: "01" is a valid code, "1/2" might be a fraction or a date, and a stray comma splits one cell into two. This converter keeps every cell exactly as written, which is why the result is predictable even for messy exports.

If your downstream system expects numbers, apply that conversion explicitly — for example by mapping a column with the tool of your choice — so the change is deliberate and reviewable.

Choosing the header option

With the header row enabled, the first line supplies the JSON keys; duplicate or empty headers become "column N". Turn the option off to produce an array of arrays instead, which is what you want for files without a header.

Frequently asked questions

Does CSV to JSON Converter upload my files to any server?

No. CSV to JSON Converter runs in your browser, and the file is read there rather than sent to a server for processing. Our host still sees ordinary page-request metadata, which is described on the privacy page.

Is CSV to JSON Converter free to use?

Yes, CSV to JSON Converter is free, with no paid tier, no account, and no watermark added to your output. The limits are technical rather than commercial: file size, page count and supported formats are listed on this page.

What file formats and sizes are supported?

CSV to JSON Converter supports .csv, .txt, .tsv files up to 25MB directly in your browser.

Are numbers converted to numbers?

No. Every value stays a string. Guessing types would turn "01" into 1 and "1e5" into 100000, and you would get no warning. If you need typed values, run a schema on the output.

Does it handle quoted commas and embedded newlines?

Yes. The parser follows RFC 4180: a quoted field may contain commas, double quotes (escaped by doubling) and line breaks. The delimiter is detected automatically for common separators.

What happens to a ragged row with too few cells?

Missing cells become empty strings for the missing columns. Rows with extra cells are reported by the parser findings, not silently dropped.

Is my data uploaded?

No. The conversion runs in this tab. The tool makes no network request with your data; only the page assets are fetched from this site.