Free CSV to JSON Converter
Convert CSV data to JSON instantly in your browser. Paste raw CSV or upload a file — the converter auto-detects commas, semicolons, tabs, and pipes. Choose whether to use the first row as headers, toggle between pretty-printed and compact JSON output, preview the first rows as a table, then copy or download the result. All processing happens client-side; your data never leaves your device.
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Auto-detects delimiter
Comma, semicolon, tab, and pipe delimiters are detected automatically from the first few hundred characters.
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Headers or no headers
Toggle whether the first row contains column names. Without headers, columns are named column1, column2, etc.
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100% private
All conversion happens in your browser. Your CSV data is never sent to any server.
Frequently Asked Questions
What delimiters are supported?+
The converter auto-detects the most common delimiters: comma (,), semicolon (;), tab (\t), and pipe (|). You can also override the detected delimiter manually.
Does it handle CSV files with quoted fields?+
Yes. Fields wrapped in double quotes — including those containing commas or newlines — are handled correctly per the RFC 4180 CSV standard.
What happens to empty cells?+
Empty cells are converted to empty strings ("") by default, which keeps the JSON structure consistent. Every row will have the same set of keys.
Is there a file size limit?+
No artificial limit is enforced. The tool processes data in-browser so performance depends on your device. Files up to a few MB convert instantly; very large files (50 MB+) may take a second or two.
What JSON structure does the output use?+
When "First row as headers" is enabled (default), the output is an array of objects — each row becomes an object with keys from the header row. With headers off, each row becomes an array of values, and the output is an array of arrays.
Is my CSV data safe?+
Yes. All conversion happens locally in your browser. Your CSV data — including any sensitive values — is never sent to any server.
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CSV and JSON: Two Formats, One Converter
CSV (Comma-Separated Values) is the de facto standard for tabular data exports — spreadsheets, database dumps, analytics reports, and CRM exports all default to CSV. JSON (JavaScript Object Notation) is the standard for APIs, configuration files, and modern web applications. Converting between the two is one of the most common data-wrangling tasks for developers, analysts, and anyone building data pipelines.
How the CSV Parser Works
The converter parses CSV according to RFC 4180: double-quoted fields can contain commas, newlines, and escaped double quotes (""). The delimiter is auto-detected by counting the frequency of common separators outside of quoted fields in the first 2,000 characters. You can override it manually if your file uses an unusual separator.
When to Use an Array of Objects vs an Array of Arrays
With "First row as headers" enabled (the default), each CSV row becomes a JSON object — keys come from the header row. This is the format expected by most APIs and databases. With headers off, each row becomes an array of values. Use the headerless format when you need to preserve raw positional data or the CSV has no meaningful column names.
Handling Large CSV Files
The converter processes the entire file in the browser. Files under 10 MB convert in milliseconds. For files in the 50–200 MB range, modern browsers handle them fine but the display preview is limited to 5 rows to keep the UI responsive — the downloaded JSON will contain all rows. For files above 200 MB, a server-side or command-line tool (such as csvtojson in Node.js) will be faster.