CSV to JSON Converter
Paste your CSV, pick the separator, and get valid JSON you can use straight away in an API call or a test file. Everything happens in your browser, so your data never leaves this page.
How to use this tool
- 1Choose what you are converting from and to. The middle button swaps the direction.
- 2Paste your data into the left box, or upload a file of up to 5MB.
- 3The converted result appears on the right as you type.
- 4Press Copy, or Save file to download it. Excel always downloads, because a spreadsheet cannot be shown as text.
Why the delimiter matters
"CSV" is not one single format. Files exported in Europe often use semicolons, because there the comma is used as a decimal point. Files coming out of a database often use tabs. Auto-detect handles most of it, but you can always set it yourself in Settings.
What happens to nested data
A table has rows and columns, and JSON does not have to. When JSON goes into a table, a nested object or array is written into the cell as JSON text rather than being thrown away. Converting back gives you that text again, so nothing is lost even though the shape flattens.
Opening the result without damage
Spreadsheet apps change your data while importing a CSV. Long numbers become scientific notation, and anything that looks like a date gets converted into one. If your data has IDs, phone numbers or product codes, convert to Excel instead. The values are stored with their type, so nothing gets reinterpreted on the way in.
Frequently asked questions
Is my file uploaded anywhere?
No. The file is read by your own browser and the whole conversion happens on your computer. No request goes out to any server, which is why the tool keeps working even if your internet stops after the page has loaded.
Which formats can it convert between?
CSV, TSV, JSON and Excel, in any direction. Excel can only come in as an uploaded file and can only go out as a download, because a spreadsheet is a binary file and not text.
What does auto-detect do for the delimiter?
It reads the first line of your data and tries a comma, tab, semicolon and pipe, then keeps whichever one splits it into the most columns. Set the delimiter yourself if your values contain commas and are not wrapped in quotes.
Why are my PIN codes losing their starting zeros?
Numbers become real numbers in JSON, so 011234 turns into 11234. Switch on "Surround non-numbers in quotes" to keep every value as text. Do this for PIN codes, phone numbers and any code that only looks like a number.
What is "remove empty trailing columns" for?
Spreadsheet exports often carry a tail of empty columns that nobody typed into. This drops any column at the far right that is empty in the heading and in every single row. It is on by default because it is almost always what you want.
How large a file can it handle?
Uploads are capped at 5MB. Pasted text has no limit beyond your own computer memory, since nothing is being sent anywhere.
More free tools you can open
See all tools →Click any card below to open that tool. All of them are free.
- ConvertersComma Separator – Column to CSVComma Separator tool to quickly add commas between words, numbers or lines. Format and separate your text online with ease.Open this tool
- ConvertersColumn to Comma Separated ListColumn to Comma Separated List turns a spreadsheet column into one comma-separated line. Add quotes for SQL, or tags for HTML, and copy the result.Open this tool
- ConvertersJSON to CSV ConverterJSON to CSV Converter helps you quickly transform JSON data into CSV format online. Convert structured data easily and efficiently.Open this tool
- ConvertersUppercase to Lowercase ConverterUppercase to Lowercase Converter quickly changes capital letters into lowercase text. Convert and format your text online for free.Open this tool
- ConvertersWord CounterWord Counter counts words, characters, sentences and paragraphs as you type, with reading time, speaking time and a readability score. Free, nothing uploaded.Open this tool
- ConvertersSquare Your Image ToolSquare Image Tool lets you easily crop or resize images into a perfect square. Create square images online quickly and easily.Open this tool