Are formulas evaluated?

The grid shows the cached cell values stored in the workbook (what Excel last calculated). Formulas themselves are not re-evaluated in the browser, so volatile functions like NOW() will show their saved result.

How large a workbook can I open?

Hundreds of thousands of rows are fine, but only the first 5,000 visible rows on the active sheet render at once — use the filter to drill into the rest.

Does it support .xlsm and .xlsb?

Yes — macro-enabled (.xlsm) and binary (.xlsb) workbooks both parse via SheetJS. Macros themselves are not executed.

Documents.xlsx · .xlsm · .xlsb

XLSX viewer

ready

XLSX · .xlsx · .xlsm · .xlsb

Open XLSX files

Microsoft Excel OOXML spreadsheet.

Choose a fileor paste · ⌘V

About XLSX

Microsoft Excel OOXML spreadsheet.

XLSX is Excel's modern OOXML container — a ZIP archive holding one worksheet XML part per tab plus shared strings, styles, and any embedded charts. This viewer parses workbooks entirely client-side with SheetJS, surfacing every sheet as a tab and computed cell values in a fast, scrollable grid. Numeric cells right-align with tabular numerals; dates are normalised to ISO. Filter narrows the visible rows on the active sheet in real time. Files never leave your browser — useful for quick spreadsheet inspection without launching Excel.

FAQ

Are formulas evaluated?: The grid shows the cached cell values stored in the workbook (what Excel last calculated). Formulas themselves are not re-evaluated in the browser, so volatile functions like NOW() will show their saved result.
How large a workbook can I open?: Hundreds of thousands of rows are fine, but only the first 5,000 visible rows on the active sheet render at once — use the filter to drill into the rest.
Does it support .xlsm and .xlsb?: Yes — macro-enabled (.xlsm) and binary (.xlsb) workbooks both parse via SheetJS. Macros themselves are not executed.