CSV to JSON Converter

Convert CSV to JSON format free online. Transform data instantly, copy results. Browser-based, no registration, instant conversion, secure.

Free online file converter tool. Works in Chrome Firefox Safari Edge Opera and other modern browsers on Windows macOS Linux Android and iOS. No software installation required. Browser-side processing keeps your file local when supported. Completely free to use with no account needed.

CSV to JSON Converter

Convert CSV spreadsheet data to JSON arrays instantly in your browser.

CSV to JSON Features

Accurate CSV parsing with automatic delimiter detection.

Auto-Detect Delimiter

Automatically detects comma, semicolon, tab, and pipe delimiters.

Header Row

First row used as JSON keys for clean output.

Quoted Values

Properly handles quoted CSV values containing commas.

How to Convert CSV to JSON

  1. Paste your CSV and set the delimiter

    Paste your CSV into the input box, making sure the first line is the header row. Then pick the matching delimiter button - comma, semicolon, or tab - so the columns split correctly. The conversion runs in your browser, so nothing is sent to a server.

  2. Click Convert to JSON

    The first row becomes the object keys and every following non-empty line becomes one object in the array. Quoted fields that contain the delimiter, and doubled quotes inside them, are parsed correctly. The output appears pretty-printed with two-space indentation.

  3. Copy or reuse the result

    Use the Copy button to place the JSON array on your clipboard, ready to paste into code, an API request, or a config file. Click Clear to empty both boxes and start over with new data.

CSV vs JSON for Working With Data

CSV and JSON describe the same tabular data in very different shapes. CSV is compact and spreadsheet-friendly, while JSON is structured and ready for code. The table below shows where each format fits and what this converter produces when it bridges the two.

AspectCSV (input)JSON (output)
StructureRows and columns separated by a delimiterArray of objects with named keys
Keys / headersSingle header line on topHeader values become each object's keys
Best forSpreadsheets, exports, bulk editingAPIs, JavaScript, config, NoSQL stores
Value typesEverything is plain textThis tool keeps values as strings, not numbers or booleans
NestingFlat onlyFlat objects here, one level per row
Readability in codeNeeds parsing to useLoads directly with JSON.parse

Is This Converter Right for Your Data

Quick API payloads

Great fit. Turn a small spreadsheet export into a JSON array you can drop straight into a request body or a test fixture, all in the browser.

Standard delimited files

Good fit. Comma, semicolon, and tab separated data with a clear header row converts cleanly, including quoted fields that contain the delimiter.

Typed or nested output

Limited. Every value stays a string and each row maps to a flat object. If you need real numbers, booleans, or nested objects, post-process the JSON afterward.

Very large datasets

Use with care. Conversion happens in memory in your browser, so multi-megabyte files may be slow. For huge files a streaming command-line tool is a better choice.

Common Problems and Fixes

Columns end up merged into one key

The selected delimiter does not match your file. If your data uses semicolons or tabs instead of commas, click the matching delimiter button before converting so each column splits correctly.

"CSV must have at least a header row and one data row"

The input has fewer than two lines. The first line is always treated as headers, so you need at least one more line of values below it for the converter to produce objects.

Numbers appear wrapped in quotes

This is expected. The converter preserves every field as a string and does not guess types, which avoids corrupting IDs or codes with leading zeros. Convert specific fields to numbers in your own code if needed.

Some rows are missing or shifted

Blank lines are skipped, and a row with fewer values than headers leaves the extra keys as empty strings. Make sure commas inside a value are wrapped in double quotes so they are not read as column breaks.

References

  1. RFC 4180: Common Format for CSV Files - IETF
  2. RFC 8259: The JSON Data Interchange Format - IETF
  3. JSON - MDN Web Docs, Mozilla
  4. FileReader - MDN Web Docs, Mozilla
  5. Comma-separated values - overview
  6. Clipboard.writeText() - MDN Web Docs, Mozilla
  7. Blob - MDN Web Docs, Mozilla
  8. JSON.stringify() - MDN Web Docs, Mozilla