How to Convert CSV to JSON
CSV is what spreadsheets and databases export; JSON is what APIs and applications actually consume. Moving between them sounds like a one-line job — split on commas, done — and that assumption is where most conversions quietly break. Real CSV files contain commas inside quoted fields, line breaks inside cells, and escaped quotes, all of which are perfectly legal and all of which destroy a naive parser. This tool implements the actual specification, so your data comes out the shape it went in.
Paste or load your CSV
Type it, paste it, or drop a file onto the input box. Nothing is uploaded anywhere.
Check the settings
The delimiter is detected automatically. Decide whether the first row is a header and whether numbers should be converted.
Convert and take the JSON
Copy it straight to your clipboard or download a .json file, with a summary of rows, columns and any warnings.
Why Splitting on Commas Fails
Consider a single row containing a name written as "Singh, Anita". Split that line on commas and you get two fields where there should be one, every subsequent column shifts by one position, and the entire row is corrupted — silently. Add a customer address with a line break in it and a simple parser will treat one record as two.
The fix is to walk the text character by character, tracking whether you are currently inside a quoted field. Inside quotes, commas and newlines are ordinary characters; outside them, they are separators. A doubled quote inside a quoted field means one literal quote. That is the whole of RFC 4180, and it is what this tool implements.
Type inference deserves a warning too. Converting "42" to the number 42 is usually what you want. Converting a product code like "007" to 7, or a long ID to a number that loses precision, is a disaster. This tool only converts a value when the number round-trips back to exactly the same text, which protects leading zeros, phone numbers and large identifiers automatically. If your data is full of codes that look numeric, switch inference off entirely.
Common Situations This Tool Solves
Feeding a spreadsheet export into an API
Most APIs accept JSON and nothing else. Converting a CSV export is usually the last step between a spreadsheet and a working integration.
Seeding test or demo data
Building sample data in a spreadsheet is far quicker than writing JSON by hand. Convert it once and paste the result into your fixtures.
Loading data into a JavaScript app
A JSON array of objects can be imported directly and mapped over. CSV needs a parser bundled just to read it.
Checking what is actually in a CSV
JSON with named keys is far easier to scan than a wall of commas, which makes it a genuinely useful way to inspect an unfamiliar export.
Frequently Asked Questions
How do I convert CSV to JSON for free?
Paste your CSV or drop a file, check the settings, and click Convert. Free, no signup, and nothing is uploaded.
Is my data uploaded to a server?
No. The parsing happens entirely inside your browser, which matters when the CSV contains customer records or anything confidential.
Does it handle commas inside quoted fields?
Yes. It implements the RFC 4180 specification properly, so quoted commas, embedded line breaks and escaped quotes are all parsed correctly.
What if my file uses semicolons or tabs?
The delimiter is detected automatically by testing which one produces the most consistent column count. You can also set it manually.
What does type inference do?
It converts text like 42 into a number and true into a boolean. It only does so when the value round-trips exactly, which protects leading zeros and long IDs.
Why did my ID with leading zeros stay as text?
Deliberately. Converting 007 to 7 would lose information, so values that do not round-trip exactly are left as strings.
What if my CSV has no header row?
Untick the header option and columns are named column_1, column_2 and so on, with every row treated as data.
Can I create nested JSON?
Yes. Tick Nest dotted columns and a header like user.name produces a nested object rather than a flat key.
What happens if rows have different column counts?
Missing values are left empty and you get a warning telling you how many rows were affected, so nothing fails silently.
Is there a file size limit?
Files above about 20 MB are rejected because browser parsing becomes very slow. For larger data, work with an extract or a command-line tool.
Does it handle files exported from Excel?
Yes, including the byte order mark Excel adds to UTF-8 files, which otherwise appears as stray characters in the first column name.
Is this CSV to JSON converter really free?
Completely free, with no limits, no signup and no premium wall. Everything runs in your browser.
Last updated: July 21, 2026 · FlipMyFormat CSV to JSON
Written and maintained by the FlipMyFormat team