Excel to JSON/CSV
Convert Excel files (XLSX or XLS) to JSON or CSV. Data types are preserved, so numbers stay numbers and dates come out in the format you choose.
Your file needs:
- A unique column header in every cell of row 1
- No empty columns between headers
- Data starting from row 2
- Nothing uploaded
- No size limit
- No account
Drag and drop an Excel file here, or click to select
What the Excel to JSON/CSV tool does
Spreadsheets are for people; JSON and CSV are for programs. This converter turns an Excel worksheet into either format, using the first row as field names and keeping data types intact — numbers stay numbers, booleans stay booleans, and dates come out in a format you choose rather than as Excel serial numbers.
How to convert an Excel file to JSON or CSV
Add a workbook with headers in the first row
Drop an .xlsx or .xls file. The first row must hold a unique, non-empty name for every column, since those become your JSON keys or CSV headers. The file is checked as soon as you add it, so problems surface before you convert.
Pick JSON or CSV
JSON gives you an array of objects, one per row, with real numbers and booleans. CSV gives you a comma-separated file with values quoted and escaped wherever they contain a comma, quote or line break.
Choose a date format and convert
For CSV, pick from ISO, US, UK/EU, and the two with a time component. JSON always uses ISO 8601, the format nearly every language and database parses without help.
Options explained
What stays on your device
Your workbook is never uploaded. The Excel to JSON/CSV tool reads the file straight from your disk and does all of its work inside this browser tab, using the open-source ExcelJS and SheetJS libraries. There is no account, no upload limit and no copy of your data on any server — once this page has loaded, the tool keeps working even if you disconnect from the internet.
Limitations to know about
- Only the first worksheet is converted.
- Every column needs a unique, non-empty header in row 1, and there must be at least one row of data beneath it. The file is rejected with a specific message if not.
- Formula cells export their last calculated result, so a workbook saved without calculating will export empty values for them.
- Cell formatting, colours and number formats are not represented in JSON or CSV — only values are.
- Hyperlinks and rich text export as empty in CSV; use JSON if you need their text.
Frequently asked questions
How do I convert an Excel file to JSON?
Drop your .xlsx above, choose JSON and convert. Each row becomes an object whose keys are your column headers, and the file downloads as .json ready to feed into an API, a script or a database import.
Why do my dates come out as numbers elsewhere?
Excel stores dates as serial numbers counting from 1900, so tools that read the raw cell see a number such as 45700. This converter reads the cell as a date and writes it as ISO 8601 in JSON, or in the format you pick for CSV, so it stays a date everywhere downstream.
Does the CSV handle commas inside a value?
Yes. Any value containing a comma, a double quote or a line break is wrapped in double quotes, and quotes inside it are doubled, which is the standard CSV escaping that Excel and most parsers expect.
What is the difference between exporting CSV from Excel and using this?
Excel's own export uses your machine's regional settings for dates and decimals, which is a common source of files that break on someone else's computer. Here you choose the date format explicitly, and JSON output additionally preserves the difference between numbers, booleans and text.
Are my files uploaded to a server?
No. Every tool on Excel Toolbox runs in your browser using the open-source ExcelJS and SheetJS libraries. Your workbook is read from your own disk, processed in your browser tab, and written back out as a download. It is never sent to us or to anyone else, which is why the tools keep working if you go offline after the page has loaded.
How large a file can I process?
There is no upload limit, because nothing is uploaded — the ceiling is your device's memory. Files up to about 25 MB are comfortable on a typical laptop. Much larger workbooks will still work but take longer, and processing runs in the page, so leave the tab open until your download starts.