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XLSX viewer
Drop an .xlsx and read it: pick any sheet, search across every column, sort by clicking a header, and export what you are looking at as CSV or .xlsx. You do not need Excel installed and the workbook is never uploaded — it is unzipped and parsed by JavaScript in this tab.
Open a workbook
Drop .xlsx, .xlsm or .csv here, or click to choose
Nothing is uploaded. The file is read by JavaScript in this tab and never leaves your computer — no server sees it, and closing the tab throws it away.
What an .xlsx actually is, and why a browser can open it
An .xlsx file is a ZIP archive of XML documents: one per worksheet, plus a shared table of every string
in the workbook and a table of number formats. Modern browsers can unzip on their own
(DecompressionStream, Chrome 103+, Safari 16.4+, Firefox 113+), which is why this page can
read a workbook without a server and without a 1.5 MB library.
The sheet picker lists hidden sheets too
A workbook you were sent often keeps the real table on a sheet that is hidden in Excel — a staging tab, last quarter's data, the lookup list a formula points at. Every sheet in the file is listed with its row count, hidden or not, because the point of opening someone else's workbook is to see what is in it.
Formulas show the value Excel last calculated
A formula cell stores both the formula and its cached result, and the result is what you see here. That is normally what you want. The exception is a workbook written by a program that never recalculated — those cells are blank, and the fix is to open it once in Excel or LibreOffice and save.
Past what one sheet holds
One Excel worksheet holds 1,048,576 rows. A file with more than that opens here and the row count above the table says how many rows are past the limit, which is the fact you came for if Excel truncated the file silently. What to do about it: working past the Excel row limit.
Reading is not the same as trusting
A workbook from outside the company is worth reading before it is worth acting on — and the questions are usually which sheet is current, what changed since the last one, and whether the totals add up.
TableDI 2 is a desktop app for file work you redo every period: it keeps your sources, rules and delivery as a job, so next month you drop in the new files and run it again. Everything runs on your own machine.
Questions people ask
Do I need Excel installed to open an .xlsx?
No. This page unzips and parses the workbook in your browser, so any computer with a recent browser can read it — including a phone. Reading .xlsx needs Chrome 103+, Safari 16.4+ or Firefox 113+; older browsers are told so rather than failing quietly.
Are my files uploaded anywhere?
No. The file is read by JavaScript running in this tab, using the browser's own
DecompressionStream to unzip .xlsx and a parser that runs on your machine. There is no
server call in the page — you can watch the network tab while you use it. Close the tab and the data is gone.
Can I see hidden sheets?
Yes. Every sheet in the file is in the picker with its row count, including ones hidden in Excel.
Can I edit the workbook here?
You can search, sort and export a view of it, but cells are not written back. A browser tab is a poor place to keep the only copy of anything — export to .xlsx and edit it in your spreadsheet program.
What about formulas, charts and formatting?
Formulas show their last calculated value. Charts, images, pivot caches and cell formatting are not rendered — this is a viewer for the data, not a spreadsheet program.
Does it work with old .xls files?
Not directly. The .xls format is a different, binary format from Excel 97. Open it in Excel, LibreOffice or Numbers and save as .xlsx or .csv, then come back. The tool tells you this rather than failing silently.
Is there a file size limit?
No fixed one; the constraint is your browser tab's memory. The table pages 100 rows at a time so a very large sheet stays responsive instead of rendering all at once.
Related
Doing this every month?
TableDI 2 keeps it as a job — the files, the key columns, the tolerance and the fixes you made. Next month you drop in the new files and run it again.
macOS, Apple silicon and Intel; Windows is in progress. Free is not a trial — no account, no card.
Last reviewed 2026-09-15 by the TableDI team. Something wrong on this page? Tell us — it is one inbox, read by the people who build TableDI.