CSV to JSON Converter
Convert CSV to a JSON array of objects using the header row as keys, or to an array of arrays. Numbers and booleans can be typed automatically; delimiters are detected.
When does a CSV field need quotes?
RFC 4180 has one core rule: if a field contains the delimiter, a double quote or a line break, wrap it in double quotes and double any quotes inside. Type a value and watch the row that gets written.
1,"Portland, OR",active
- contains the delimiter (,)
- contains a double quote, so each " is doubled to ""
- contains a line break
- has leading/trailing spaces (quoting keeps them; not required by RFC 4180, but many parsers trim)
Quotes required.
Written row, exactly: 1,"Portland, OR",active
How it works
Parsing follows RFC 4180 quoting, so commas and line breaks inside quoted fields are handled.
With "detect types" on, 42 becomes a number and true a boolean. Turn it off to keep everything as strings, which is safer for IDs and ZIP codes with leading zeros.
Everything above runs in JavaScript inside this tab. Your data is not uploaded. Inputs are remembered in this browser only so they survive a reload; you can switch that off on the privacy page.
Questions
Why did my ZIP code lose its leading zero?
Type detection turned "02134" into the number 2134. Switch off "detect types" to keep values as strings.
Can I convert a file without a header row?
Yes. Turn off "first row is header" to get an array of arrays.
Is my CSV sent to a server?
No. Conversion happens in your browser. The only network request is the optional AI explanation when your input has an error and you ask for it.