noun

XLSX

EKS-el-ESS-eks

XLSX (noun) means the standard file format for spreadsheets used by Microsoft Excel since 2007, based on the Office Open XML standard. It stores the cells, formulas, formatting, charts and multiple sheets of a workbook inside a single compressed package. Example: “The finance team sent over the budget as an XLSX with four tabs.”

noun

technical, computing The standard file format for spreadsheets used by Microsoft Excel since 2007, based on the Office Open XML standard. It stores the cells, formulas, formatting, charts and multiple sheets of a workbook inside a single compressed package.

"The finance team sent over the budget as an XLSX with four tabs."

"Export it to XLSX if you want the formulas to survive."

How to Use XLSX

Learner’s notes

In plain EnglishThe normal file type for an Excel spreadsheet.

When to use it

Technical but common in office and finance settings. Often written as the extension .xlsx.

Memory tip

Most people just say "an Excel file" out loud and write XLSX only when the exact format matters.

Trace the full origin ↓

Easily confused with

XLS CSV → XLSM ODS →

Common pairings

XLSX file .xlsx export to XLSX convert CSV to XLSX

Study it as flashcards or scroll it in Flow — saved to your collection.

Test yourself on “XLSX” A quick quiz — meaning, synonyms & usage →

Fill the Gap

Can you complete this real example?

The finance team sent over the budget as an _____ with four tabs.

Etymology

From xls, the older extension for a Microsoft Excel spreadsheet, plus x for XML, the text-based system used to store the file's contents.

Origin: English

Synonyms

View more →

Excel file Excel workbook spreadsheet file workbook

Frequently Asked Questions

What is the difference between XLSX and CSV?

A CSV is a plain list of values separated by commas, one row per line, with no formatting, no formulas and only one sheet. XLSX keeps everything a spreadsheet program can do: several sheets, live formulas, cell colours, charts and number formats. CSV travels between systems more easily; XLSX preserves the actual spreadsheet.

What is the difference between XLS and XLSX?

XLS is the older binary Excel format; XLSX replaced it in 2007 with a zipped, XML-based structure. XLSX files are generally smaller, less fragile and support far more rows — just over a million per sheet, against the 65,536 limit of XLS.

Can I open an XLSX without Excel?

Yes. Google Sheets, LibreOffice Calc, Apple Numbers and various free viewers all read XLSX. Uncommon features such as certain chart types or macros may not carry across intact.