How does CSV convert to JSON?

The header row becomes the object keys, and each subsequent row becomes one JSON object whose values are matched to those keys by column. All the objects are collected into a single JSON array.

Will numbers stay as numbers or become strings?

That's your choice. Type conversion turns numeric and true/false values into real JSON numbers and booleans, which is convenient for code. Keeping everything as strings is safer for IDs, ZIP codes and anything with leading zeros.

What if my CSV uses semicolons instead of commas?

That's common in spreadsheets from some locales. Set the delimiter to a semicolon (or tab, for TSV files) so the tool splits each row into the correct columns before building the JSON.

Can it handle values that contain commas?

Yes, as long as those values are wrapped in double quotes in the CSV, which is the standard way to escape them. The parser treats a quoted field as a single value even if it contains commas or line breaks.

Is my data uploaded to a server?

No. The conversion happens entirely in your browser, so your CSV never leaves your device. That makes it safe to convert files containing personal or sensitive data.

7 steps

How to Convert CSV to JSON (Free, In Your Browser)

Turn a spreadsheet or CSV export into a clean array of JSON objects, with the right headers as keys and correct data types. A step-by-step guide.

CSV is perfect for spreadsheets but awkward for code: most APIs, config files and JavaScript apps expect JSON instead. Converting turns each row of your CSV into a JSON object, with the header row becoming the keys, so you get a clean array you can drop straight into a program or request body.

The tricky parts are getting the delimiter right, deciding whether numbers and booleans should stay as text or be typed, and handling quoted fields that contain commas. This guide covers all of that using our free CSV-to-JSON converter, which runs entirely in your browser so your data never leaves your device.

This guide uses CSV to JSON

Free, private and instant. Open it now and follow along with the steps below.

Open CSV to JSON

Follow these steps

Step 1: Open the CSV to JSON converter
Go to the CSV-to-JSON tool. It runs in the browser with nothing to install, and your file is processed locally. Nothing is uploaded.
Step 2: Paste or upload your CSV
Drop in a .csv file exported from Excel, Google Sheets or a database, or paste the raw CSV text directly. Make sure the first row contains your column headers.
Step 3: Confirm the delimiter
Most files use commas, but some use semicolons or tabs: common in European locales or TSV exports. Check the detected delimiter matches your data so columns split correctly.
Step 4: Check that the header row maps to keys
The first row's values become the JSON property names. Verify the headers are clean (no stray spaces or duplicates) so you get sensible keys like "email" rather than " Email ".
Step 5: Decide how to handle data types
Choose whether numeric and boolean-looking values should be converted to real numbers and booleans, or kept as strings. Typed output is handier for code. String output preserves things like leading zeros in IDs and ZIP codes.
Step 6: Convert to JSON
Run the conversion. Each row becomes an object keyed by your headers, and the whole file becomes a JSON array: formatted and ready to read.
Step 7: Copy or download the JSON
Copy the result to your clipboard or download it as a .json file to use in your app, API request or data pipeline.

Tips & best practices

Keep leading zeros as strings: if you convert an ID or ZIP code like 00123 to a number it becomes 123 and you lose the zeros.
Watch for fields that contain commas: they must be wrapped in double quotes in the CSV, otherwise the row splits into the wrong number of columns.
Clean your headers before converting, trailing spaces or duplicate column names produce awkward or colliding JSON keys.
If a value could be misread (a phone number, a version like 1.10), keep it as a string so the conversion doesn't reformat it.

Related tools

JSON to CSV

Convert JSON to CSV in your browser. Paste an array of objects and get a spreadsheet-ready CSV with a header row, automatic flattening of nested keys, and a choice of comma, semicolon or tab delimiter. Copy or download instantly. Nothing is uploaded.

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JSON Formatter

Format, validate and minify JSON in your browser with pinpoint error line + column, jump-to-error, key sorting and live editing: nothing is uploaded.

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CSV to Excel

Convert CSV to a real Excel.xlsx file in your browser. Paste or drop a.csv, preview the parsed grid live, name the sheet, and download a workbook that opens natively in Excel, Google Sheets and LibreOffice. Delimiter is auto-detected. Nothing is uploaded.

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JSON Validator

Validate JSON against RFC 8259 with the exact error line, column and a caret under the bad character. Get plain-English explanations, one-click auto-fix for trailing commas and single quotes, plus depth, key-count and type stats, nothing uploaded.

Developer Studio

How to Convert CSV to JSON (Free, In Your Browser)

Follow these steps

Step 1: Open the CSV to JSON converter

Step 2: Paste or upload your CSV

Step 3: Confirm the delimiter

Step 4: Check that the header row maps to keys

Step 5: Decide how to handle data types

Step 6: Convert to JSON

Step 7: Copy or download the JSON