XLSB to XLSX Converter
Processing entirely on your device — large files may take a moment.
Convert to XLSX when the data needs real spreadsheet power — sorting, filtering, formulas — or must be shared with Excel users. If your files are still in XLSB format, this page is the shortcut: XLSB is Excel's binary workbook format: identical content model to XLSX, packed in a binary container that opens and calculates faster on huge sheets.
This converter runs entirely in your browser using WebAssembly — your files never leave your device, nothing is uploaded, and there are no watermarks, sign-ups or queues. Drop in several files at once to convert them as a batch.
How XLSB compares to XLSX
| XLSB | XLSX | |
|---|---|---|
| Structure | Binary OOXML container (.bin parts) | Multiple sheets |
| Types / schema | Same cell model as XLSX | Typed cells + formulas |
| Compatibility | Excel 2007+, SheetJS | Excel 2007+, LibreOffice, Sheets |
| Best for | Very large calculation-heavy workbooks | Finance, analysis, models |
How to convert XLSB to XLSX
- 1
Select your files
Drag & drop your XLSB files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to XLSX". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted XLSX file individually, or grab everything at once as a ZIP archive.
About the XLSB format
XLSB is Excel's binary workbook format: the same content model as XLSX but packed in a binary container instead of XML. It opens and calculates noticeably faster on huge sheets and produces smaller files — the tradeoff is that almost nothing outside Excel can read it, and macro-bearing workbooks cannot use it at all.
Because the cell data is identical to XLSX, converting XLSB to CSV, JSON or XLSX loses nothing: SheetJS parses the binary parts natively in your browser, and the output is an ordinary spreadsheet that every tool accepts. If you only need the values, CSV is the shortest path.
+ Strengths
- ✓Faster open/calc and smaller files on huge sheets
- ✓Full fidelity to XLSX content model
- ✓Reads natively in-browser (SheetJS) — no upload
! Limitations
- −Opaque binary — no diffing or git-friendliness
- −Cannot hold VBA macros
- −Few third-party readers outside Excel/SheetJS
About the XLSX format
XLSX is the modern Excel workbook (default since Excel 2007, same OOXML zip-package idea as DOCX). One file can carry multiple sheets, typed cells, formulas that recalculate, charts, conditional formatting and pivot caches — a small application, not just a table. LibreOffice, Google Sheets and WPS open it natively, and server-side libraries can read and write it without Excel installed.
Being a spreadsheet program's file, it is a poor plain-data exchange format: formulas reference cell positions that break when rows are reordered, hidden sheets and cached values surprise consumers, and the zip package is heavier than CSV. For analysis and finance it is the right tool; for pipelines, export the CSV.
+ Strengths
- ✓Multi-sheet with formulas, charts and formatting
- ✓Typed cells and recalculation
- ✓Opens natively across the office ecosystem
! Limitations
- −Heavier and less diff-friendly than CSV
- −Formulas tie data to cell positions
- −Hidden state (sheets, caches) surprises downstream tools
Why convert XLSB to XLSX?
Converting makes sense where the strengths of XLSX meet what XLSB cannot give you. Multi-sheet with formulas, charts and formatting Meanwhile Opaque binary — no diffing or git-friendliness One pass through the converter above puts your file on the right side of that trade-off.
Frequently asked questions
Is this XLSB to XLSX converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
What about special characters and non-English text?
Everything is handled as UTF-8. When you export CSV for Excel, a UTF-8 BOM is included automatically so Chinese, Japanese, Korean and accented characters display correctly on both Windows and macOS.
Are formulas, styles or multiple sheets converted?
No — this conversion extracts the data itself into XLSX. Formulas are exported as their current values, styling is not carried over, and multi-sheet workbooks convert sheet by sheet. For full fidelity between spreadsheet formats, exchange within the same tool family.
Is my data safe here?
Yes. The conversion is plain JavaScript running in your tab: the data is parsed and re-serialized in memory, never sent anywhere, and disappears when you close the page.