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Data Converter

Convert between CSV, Excel, and JSON formats

About this tool

CSV, Excel (.xlsx), and JSON are the three formats data moves around in: CSV is the lowest-common-denominator dump from any database; Excel is what business users open natively; JSON is what APIs and frontends consume.

This converter switches between all three, in any direction. Paste text or upload a file, pick the output format, and download the result. Conversion runs entirely in your browser — even your sensitive spreadsheets stay on your machine.

How to use

Convert data

  1. Pick paste mode (for CSV / JSON text) or upload mode (for any of the three formats).
  2. Drop the file or paste the text.
  3. Pick the output format you want.
  4. Click Convert. Copy the result, or Download as a file.

Examples

CSV → JSON

Input
name,age,city
Alice,30,NYC
Bob,25,LA
Output
[
  { "name": "Alice", "age": "30", "city": "NYC" },
  { "name": "Bob", "age": "25", "city": "LA" }
]

JSON → CSV

Input
[
  {"id":1,"label":"Apple"},
  {"id":2,"label":"Banana"}
]
Output
id,label
1,Apple
2,Banana
Frequently asked questions
How big a file can I convert?

No hard limit, but everything is loaded into browser memory. CSV / JSON up to ~50 MB usually works. Excel files become memory-heavy quickly because the parser has to expand the entire workbook — try splitting into sheets if you hit problems.

Which Excel sheets are converted?

Single-sheet workbooks convert directly. Multi-sheet workbooks let you pick which sheet to use; only one is converted at a time. To merge sheets, do the merge in Excel first or convert each separately and combine downstream.

How does CSV handle commas / quotes inside a field?

Standard RFC 4180 quoting: fields containing commas, quotes, or newlines are wrapped in double quotes, and embedded quotes are doubled. The parser auto-detects quoting on input.

What character encoding is used?

UTF-8 throughout. If you upload a CSV that was saved as GBK / Latin-1 / Windows-1252, characters may show as question marks. Re-save as UTF-8 in your source application before converting.

Does JSON → CSV handle nested objects?

Top-level keys only. Nested objects or arrays will be JSON-stringified into a single CSV cell, which is rarely what you want. Flatten nested structures first (or use a programming language with a CSV library that supports your specific schema).