Convert between CSV, Excel (XLSX and old XLS), OpenDocument (ODS) and JSON. Choose a file, pick the format, download.
How to convert a spreadsheet
- Choose a CSV, XLSX, XLS or ODS file (up to 20 MB).
- Pick the format to convert to. For CSV and JSON, pick the sheet if the file has several.
- Check the preview and press Convert, then download.
Which conversions
- CSV to Excel: one sheet, with numbers and true/false values typed.
- XLS to XLSX: updates Excel 97–2003 files to the current format, keeping all sheets and formulas.
- ODS to XLSX or CSV: for files from LibreOffice Calc or OpenOffice.
- Excel, ODS or CSV to JSON: for apps, scripts and APIs.
Example: CSV to JSON
This CSV, with a quoted comma in one cell:
Date,Item,Amount
2026-04-01,Rent,25000
2026-04-03,"Groceries, milk",1840.50
becomes this JSON, with the header row as names and the amounts as numbers (1840.50 is written 1840.5):
[
{ "Date": "2026-04-01", "Item": "Rent", "Amount": 25000 },
{ "Date": "2026-04-03", "Item": "Groceries, milk", "Amount": 1840.5 }
]
Converted to Excel instead, the Amount column holds numbers you can total. Text that starts with "=" stays text and never becomes a formula, so a CSV can't slip a formula into your workbook.
Only need CSV from an .xlsx file? Excel to CSV shows each sheet as CSV you can copy. For CSV to JSON with options, use the CSV ↔ JSON converter.
Frequently asked questions
How do I convert CSV to Excel?
Choose the .csv file, keep Excel (.xlsx) selected and press Convert. Numbers become real numbers you can add up; codes with leading zeros, such as 007 or PIN codes, stay as text. Commas, semicolons and tabs are all recognised as separators.
Are formulas kept?
When the result is Excel (.xlsx) or OpenDocument (.ods), formulas, number formats and every sheet are kept. CSV and JSON can only hold values, so they get the last calculated result of each formula.
Why do dates look like 2026-04-01 in CSV and JSON?
Dates are written year-month-day, the international format, so 01/04 can't be misread as 4 January or 1 April. Excel and Google Sheets recognise it when you open the file.
Can I convert Excel to JSON?
Yes. Pick JSON: each row becomes an object named by the header row, or choose 'Is data' to get plain arrays. Numbers and true/false stay typed.
Can it open password-protected spreadsheets?
No. Remove the password in Excel or LibreOffice first (in Excel: File → Info → Protect Workbook → Encrypt with Password, then clear the box).
Is my file uploaded?
No. The spreadsheet is read and written in your browser, so salary sheets and customer lists stay on your device.