How to Convert CSV to JSON in 3 Steps
To convert CSV to JSON, paste your CSV data into the Input panel — including the header row. Click Convert, and the tool uses the first row as property names and maps each subsequent row into a JSON object. The result is a JSON array where each element corresponds to one CSV row. Click Copy to grab the output or Download JSON to save it as a .json file.
The converter auto-detects whether your data uses commas, semicolons, or tabs as the delimiter, so most standard CSV files work without configuration. Quoted fields (cells that contain commas or newlines wrapped in double quotes) are handled correctly and unwrapped automatically. If a cell's value looks like a number or boolean, you can enable type inference to have the converter cast it to the appropriate JSON type — otherwise all values are treated as strings.
Type inference works column-by-column: if every non-empty value in a column parses as a valid number, all values in that column are emitted as JSON numbers rather than strings. Boolean inference follows the same pattern — cells containing exactly true or false (case-insensitive) become JSON booleans. Empty cells become JSON null when type inference is on, and empty strings when it is off. This lets you load the resulting JSON directly into a JavaScript application, a Python script, or a REST API request body without a separate parsing step. All processing runs entirely in your browser — no data is sent to a server at any point. For the reverse operation, see the related JSON to CSV Converter.
Why Use This Free CSV to JSON Converter?
- Auto-detects comma, semicolon, and tab delimiters — most CSV and TSV files work without configuration
- Correctly unwraps quoted fields, even those containing commas or newlines, per RFC 4180
- Optional type inference — numbers and booleans can be cast to their native JSON types automatically
- One-click JSON download as a .json file ready for import into any application
- 100% browser-based — your CSV data never leaves your device or touches any server
- Handles large datasets entirely in-browser with no file size upload limit
- Completely free with no rate limits, no account, and no installation required
Frequently Asked Questions
Does the first row have to be a header?
Yes, the converter assumes the first row contains column headers and uses those values as the JSON property names. If your CSV has no header row, the resulting JSON will use the first data row as keys — which produces incorrect output. In that case, manually add a header row before converting: open your CSV in a text editor, type a row of descriptive names separated by commas, and paste the updated content into the tool. The CSV specification (RFC 4180) defines the header record as optional but recommends it, and most real-world CSV files include one.
Source: RFC 4180 § 2 — Definition of the CSV Format (Header Record)
How does the tool handle quoted fields with commas or newlines inside them?
The converter follows RFC 4180, the CSV standard. Fields that contain commas, double quotes, or newlines are expected to be surrounded by double quotes in the source data (e.g., "Smith, John"). Embedded double quotes are escaped by doubling them (e.g., "He said ""hello"""). The tool correctly unwraps these quoted fields and unescapes the embedded quotes, so the JSON output contains the clean string value without the surrounding quotes. This means you can safely convert CSV exports from Excel, Google Sheets, PostgreSQL COPY, and any other RFC 4180-compliant tool.
Source: RFC 4180 — Common Format and MIME Type for CSV Files
What JSON output format does the converter produce?
The output is a JSON array of objects, where each object represents one CSV row. The keys are the column header names (from the first CSV row), and the values are the cell contents (as strings by default, or as their native types if type inference is enabled). For example, a CSV with headers name,age and rows Alice,30 and Bob,25 produces [{"name":"Alice","age":"30"},{"name":"Bob","age":"25"}] (or with type inference: age would be the number 30, not the string "30"). The output conforms to ECMA-404, the JSON data interchange standard, and is valid for use with JSON.parse() in any JavaScript runtime or the json module in Python. To format the resulting JSON for readability, paste it into our <a href="/tools/json-formatter/">JSON Formatter</a>. For the reverse conversion — JSON arrays back to CSV — use the <a href="/tools/json-to-csv/">JSON to CSV Converter</a>.
Can I convert Excel files directly?
Not directly — the tool converts CSV text, not binary .xlsx files. To convert an Excel spreadsheet: open it in Excel or Google Sheets, go to File then Save As (Excel) or File then Download then CSV (Google Sheets), choose CSV format, and save. Then paste the resulting CSV text into this tool. Excel's CSV export uses commas as delimiters and correctly quotes fields that contain commas or special characters. For .xlsx files with multiple sheets, export each sheet as a separate CSV and convert them individually.
Source: Microsoft Support — Import or export text (.txt or .csv) files
Is my CSV data secure when using this tool?
Yes. The entire conversion runs in your browser using JavaScript — no network request is made, no data is uploaded to any server, and nothing is stored or logged. This is true even for large CSV files with thousands of rows: all parsing, type inference, and JSON generation happen locally on your device. You can safely convert sensitive datasets containing personal information, financial records, or proprietary business data. Closing or refreshing the page clears all input and output immediately. You can verify this by opening your browser's DevTools Network tab during a conversion — no outbound requests will appear.
What is the difference between CSV and TSV, and does this tool support both?
CSV (Comma-Separated Values) uses commas as the field delimiter, while TSV (Tab-Separated Values) uses tab characters. TSV is common in bioinformatics, database exports from MySQL and PostgreSQL, and data copied from spreadsheet applications (when you copy cells from Excel or Google Sheets, the clipboard content is tab-separated). This tool auto-detects the delimiter by analyzing the first few lines of input, so both CSV and TSV files work without manual configuration. Semicolon-delimited files (common in European locales where commas are used as decimal separators) are also detected and handled correctly.
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