CSV to TOON Converter
Input CSV
or drop a file anywhere
Output TOON
Your TOON appears here as you type.
users[3]{id,name,role}:
1,Alice,admin
2,Bob,user
3,Cleo,userPaste data to see token savings
Convert CSV to TOON with our free online converter.
Example: CSV input and real TOON output
The output below was generated by the same conversion code the converter uses, run on this sample when the page was built.
sku,name,price,stock
SKU-104,USB-C cable,9.99,240
SKU-221,Laptop stand,34.5,58
SKU-310,Webcam cover,3.25,1200
SKU-415,Desk mat,19,0[4]{sku,name,price,stock}:
SKU-104,USB-C cable,9.99,240
SKU-221,Laptop stand,34.5,58
SKU-310,Webcam cover,3.25,1200
SKU-415,Desk mat,19,0TOON output is 7% larger than the CSV input. The same data is 252 characters as minified JSON and 373 as pretty-printed JSON. Sizes are character counts, not tokens: token counts depend on the model's tokenizer (see the tokenizer comparison). Across larger datasets, TOON averages about 43% fewer tokens than JSON (42.6%) according to the official TOON benchmark.
CSV to TOON: what changes
- CSV rows map directly onto TOON's tabular form; TOON adds a [N] row count and a {field} header. Because CSV cells are strings, numeric cells come out quoted. Convert to JSON and fix the types first if the model should see real numbers.
- Reading CSV: CSV has no types: every cell is read as a string, so 9.99 becomes "9.99" in the output (visible in the sample below). The first row must be the header, and nested data cannot be represented.
- Writing TOON: TOON saves the most on arrays of objects that share the same fields: they collapse into one header plus one row per record. Nested or non-uniform objects are written as indented key: value lines and save much less.
About CSV
Comma-Separated Values is the standard format for tabular data. Perfect for spreadsheets, data analysis, and simple data exports.
- ✓Spreadsheet compatible
- ✓Simple
- ✓Universal
- ✓Great for data analysis
About TOON
TOON (Token-Oriented Object Notation) is an indentation-based format designed for LLM prompts. It uses about 43% fewer tokens than JSON on average (42.6% in the official TOON v4.1 benchmark), ranging from about 33% on mixed/nested structures to about 59% on flat uniform tables.
- ✓About 43% fewer tokens than JSON on average
- ✓Tabular rows for uniform arrays
- ✓Lossless round trip to JSON
- ✓Readable without tooling
Why Convert CSV to TOON?
Use TOON when building LLM-powered applications, optimizing API costs, or when you need compact, readable data for AI models.
CSV to TOON: Frequently Asked Questions
How do I convert CSV to TOON?
Paste your CSV into the editor on json2toon.co. The tool detects the input and produces TOON instantly, then you copy the result. Conversion runs entirely in your browser, so nothing is uploaded to a server.
Is the CSV to TOON converter free?
Yes. Converting CSV to TOON on json2toon.co is free with no account, signup, or usage limit. A free public API is also available for automated, programmatic conversion.
Why convert CSV to TOON?
Convert CSV to TOON with our free online converter.
What should I watch out for when converting CSV to TOON?
CSV rows map directly onto TOON's tabular form; TOON adds a [N] row count and a {field} header. Because CSV cells are strings, numeric cells come out quoted. Convert to JSON and fix the types first if the model should see real numbers.
Is my data safe when I convert CSV to TOON?
Yes. The CSV to TOON conversion happens client-side in your browser. Your source data stays on your device and is never sent to or stored on a server, which makes it safe for private or sensitive payloads.