00data

XLSX

Office Open XML Workbook

XLSX is the modern Excel workbook: a ZIP archive of XML parts holding sheets, formatting, formulas and types. Unlike CSV it preserves multiple sheets, real number and date types, and column widths — which is why round-tripping through CSV loses things.

Extension: .xlsx
MIME type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
Also called: Excel, Excel workbook

01 Convert XLSX to something else

XLSX to CSV Drop a workbook. Formulas become their computed values.
XLSX to JSON Header row becomes keys. All sheets in one object, if you want.
Excel to PDF Every row on the page, nothing cropped, nothing uploaded.

02 Convert something else to XLSX

CSV to XLSX A real Excel workbook with typed cells and sized columns.
JSON to XLSX An API response, straight into a spreadsheet.

03 Related formats

JSON
CSV
TSV
XML
YAML
TOML
XLS

Opening a .xlsx file

If you landed here because something handed you a .xlsx file and nothing on your machine will open it, converting it to a format you already have a reader for is usually faster than installing new software. Every conversion above runs in this browser — the file is not uploaded, so it works on a locked-down work machine and on a file you are not allowed to send anywhere.