CSV and JSON Converter

Convert CSV to JSON or JSON to CSV with this free browser tool. Paste your data or choose a local file, check the table preview and copy or download the result. No account, software installation or upload of your data for conversion is needed.

How to convert CSV to JSON

1. Add your CSV. Paste it into Input data or select a UTF-8 .csv file. A selected file takes precedence over pasted text.
2. Choose CSV to JSON. Select the delimiter used by your data: comma, semicolon, tab or pipe.
3. Check the header setting. Leave it enabled if the first row contains column names. Disable it if every row contains data.
4. Click Convert data. Review the table and generated JSON, then copy the output or download converted.json.

With headers enabled, each data row becomes a JSON object and its column names become property names. Without headers, each row becomes an array of values.

CSV to JSON example

This CSV contains two columns and two data rows:

name,postcode
Zoë,00123
Alex,00456

With the first row treated as headers, the converter produces:

[
  {
    "name": "Zoë",
    "postcode": "00123"
  },
  {
    "name": "Alex",
    "postcode": "00456"
  }
]

CSV values remain strings. That preserves leading zeroes in postcodes, product codes and identifiers. Values such as 42 and true also become JSON strings, rather than automatically becoming numbers or booleans.

How to convert JSON to CSV

1. Paste JSON or choose a file. Use a UTF-8 .json file containing a nonempty array of objects or an array of arrays.
2. Choose JSON to CSV. Set the delimiter you want in the exported file.
3. Choose whether to include a header. For object rows, property names supply the column headings.
4. Choose how to handle nested values. Reject them with an error, or encode each nested object or array as JSON inside its CSV cell.
5. Convert and check the preview. Copy the result or download converted.csv.

For object rows, the converter collects property names across the input to build the columns. Missing properties and JSON null values become empty cells. Numbers and booleans become text in the CSV output.

Nested values are not automatically expanded into additional columns. For example, an address object stays in one cell when JSON encoding is selected. Flatten the input first if you need separate street, city and postcode columns.

Delimiters, quotes and common input problems

Choose the delimiter that separates your CSV fields. A semicolon-separated file needs the semicolon option; commas inside quoted text are part of a value. The parser supports quoted fields, escaped quotation marks, embedded line breaks and Unicode characters.

Every CSV row must have the same number of cells. When headers are enabled, names must be nonempty and unique. If conversion fails, check for an unclosed quotation mark, an extra delimiter or a missing cell. For JSON, use consistent rows: all objects or all arrays, rather than a mixture. A single standalone object is not accepted as a table.

Preview, file limits and local processing

The table preview shows the first 100 data rows, while the export contains all converted rows within the limits. The visible text output is also shortened for large results; use the copy or download action to obtain the full output.

Selected files are limited to 2 MB. Input text has a separate limit of two million characters, with up to 10,000 data rows and 200 columns. Larger datasets need to be split into smaller parts before conversion.

Your data is processed locally in your browser. The preview treats values as text and does not execute spreadsheet formulas. Exported CSV preserves formula-like values too, so review those values before opening a file in spreadsheet software that may interpret them as formulas.

If your next step is displaying CSV on a web page, you can also use our CSV to HTML table converter.