Free Online Spreadsheet Converter

ChangeThisFile supports XLSX (Excel), XLS (legacy Excel), ODS (LibreOffice/OpenOffice), CSV, TSV, JSON, and PDF for spreadsheet conversions. Most browser-based conversions use SheetJS for instant processing.

Most spreadsheet conversions run entirely in your browser using SheetJS — your data never leaves your device. Conversions involving PDF or ODS formats use LibreOffice on the server, where files are encrypted in transit and auto-deleted after processing.

Yes. Go to the XLSX to CSV converter page and drop your Excel file. The conversion runs in your browser using SheetJS. If your workbook has multiple sheets, the converter exports the first sheet. Your spreadsheet data never leaves your device.

Go to the CSV to XLSX converter page and upload your CSV file. The converter parses your CSV in the browser and produces a properly formatted XLSX file with auto-detected column types.

Formulas are not preserved when converting between spreadsheet and data formats (like XLSX to CSV). The converter exports the calculated values. Formulas are typically preserved when converting between spreadsheet formats (like XLS to XLSX) using LibreOffice.

Yes. The XLSX to JSON converter turns each row into a JSON object, using the header row as keys. The result is a JSON array of objects that you can use directly in your code or import into a database.

ODS (Open Document Spreadsheet) is an open standard spreadsheet format used by LibreOffice Calc, Apache OpenOffice Calc, and Google Sheets. It is the spreadsheet equivalent of ODT for documents.

Browser-based conversions (XLSX to CSV, XLSX to JSON, etc.) have no server-imposed size limit. Server-side conversions involving PDF or ODS have a 25MB file size limit (free tier; 500MB on Pro). Most spreadsheet files are well under this.

The converter processes the first sheet by default when converting XLSX to CSV or JSON. Each sheet would need to be converted separately. When converting between spreadsheet formats (like XLS to XLSX), all sheets are preserved.

Yes. The converter fully supports Unicode text, special characters, accented letters, CJK characters, and emoji in both input and output. CSV output uses UTF-8 encoding by default.