How to Convert .xlsb to .xlsx — 5 Free Methods (Excel, Online, Python, VBA) [2026]

What .xlsb Is — and Why You Need to Convert It

An .xlsb file is Microsoft's Excel Binary Workbook format — the same data as a .xlsx file, but stored in raw binary instead of zipped XML. It loads 3-4x faster, takes about 50% less disk space, and handles workbooks beyond Excel's million-row limit more gracefully.

So why convert it to .xlsx? Three reasons:

• Compatibility — most third-party tools (Power BI, Tableau, Python pandas, Google Sheets, web upload forms, finance ERP systems) accept .xlsx but choke on .xlsb.
• Sharing — colleagues unfamiliar with .xlsb often won't open it. .xlsx is the safe default for handoffs.
• Online editing — Excel for the Web and Office 365 read-only previews treat .xlsb as second-class; many features simply don't work.

Below are 5 methods that actually work in 2026, ranked by speed and what they preserve.

Method 1 — Microsoft Excel Built-in (Save As)

The official, fully lossless way. Works on any Excel from 2007 onward.

1. Open your .xlsb file in Excel.
2. File > Save As (or press F12).
3. In the format dropdown, choose Excel Workbook (*.xlsx).
4. Click Save.

What's preserved: 100% of formulas, charts, pivot tables, conditional formatting, data validation, named ranges.

Caveat: VBA macros stored in .xlsb need to be saved as .xlsm (macro-enabled .xlsx). If you pick plain .xlsx for a macro-containing file, Excel will warn you and strip the macros.

Method 2 — Free Online Converter (No Excel Required)

If you don't have Excel installed — perhaps on a Mac without Office, a Chromebook, or a locked-down corporate machine — use a browser-based converter.

Our free XLSB to XLSX converter handles this in about 3 seconds:

1. Drag your .xlsb file onto the upload area.
2. Click "Convert."
3. Download the .xlsx file.

What's preserved: All formulas, charts, formatting, conditional rules, named ranges. The conversion runs on enterprise-grade document engines (Aspose.Cells), the same tier of technology used in mission-critical business systems.

What it lacks vs Excel: Macros are stripped (every reputable online tool does this — it's a security measure to prevent macro-based malware from spreading). Files over 100 MB may need a desktop tool.

Method 3 — VBA Macro (Batch Conversion)

If you have hundreds of .xlsb files in a folder and want to convert them all without clicking through each one, this 12-line VBA macro does the job.

Sub BatchConvertXlsbToXlsx()
    Dim folderPath As String, fileName As String
    Dim wb As Workbook
    folderPath = "C:\YourFolder\"  ' Change to your folder
    fileName = Dir(folderPath & "*.xlsb")
    Do While fileName <> ""
        Set wb = Workbooks.Open(folderPath & fileName)
        wb.SaveAs Replace(folderPath & fileName, ".xlsb", ".xlsx"), _
                  FileFormat:=xlOpenXMLWorkbook
        wb.Close SaveChanges:=False
        fileName = Dir
    Loop
    MsgBox "All .xlsb files converted to .xlsx"
End Sub

Paste this into the VBA editor (Alt+F11), change the folder path, and run with F5.

What's preserved: Identical to Method 1 — Excel itself does the conversion under the hood.

Tip: If you'd rather not write VBA by hand, an AI tool like ExcelMaster's VBA Assistant can generate this same macro from a plain-English prompt and tweak it for variations (recursive folders, post-conversion cleanup, error logging).

Method 4 — Python (Headless / Server-Side)

For data pipelines, Jupyter notebooks, or any workflow where you can't have Excel open, Python is the right tool.

import pandas as pd

# Read .xlsb (requires the pyxlsb engine)
sheets = pd.read_excel('input.xlsb', engine='pyxlsb', sheet_name=None)

# Write to .xlsx (sheet_name=None returned a dict of all sheets)
with pd.ExcelWriter('output.xlsx', engine='openpyxl') as writer:
    for sheet_name, sheet_df in sheets.items():
        sheet_df.to_excel(writer, sheet_name=sheet_name, index=False)

Install dependencies:

pip install pandas openpyxl pyxlsb

What's preserved: Cell values only. Formulas are evaluated to their results, charts are dropped, formatting is lost. This method is for data extraction, not document fidelity.

If you need formulas and formatting preserved in a Python script, use the aspose-cells-python library instead — it's commercial but has a free tier for files under 50 KB.

Method 5 — LibreOffice (Command-Line, Cross-Platform)

LibreOffice can convert .xlsb to .xlsx headlessly on Windows, macOS, and Linux. Useful for CI pipelines, Docker jobs, and Linux servers.

# Single file
soffice --headless --convert-to xlsx input.xlsb

# All .xlsb files in a folder
soffice --headless --convert-to xlsx ./*.xlsb

What's preserved: Most formulas, basic formatting, named ranges. Charts may render slightly differently from Excel because LibreOffice has its own rendering engine. Macros are stripped.

Comparison Table — Pick the Right Method

Common Pitfalls

• "File is corrupted" error in Method 1 usually means Excel was force-closed during a previous save. Open the .xlsb in Excel first, save as .xlsx, then re-open the .xlsx fresh.
• Macros disappearing — every method except Method 1 + 3 (when saved as .xlsm) strips macros. There's no way around this; saving a macro-containing workbook as plain .xlsx (not .xlsm) deletes the macros by design.
• Formula array errors after conversion — rare, but happens when the original .xlsb used dynamic arrays (Excel 365+). If the converted .xlsx is opened in Excel 2019 or earlier, dynamic arrays become #SPILL! errors. Open in Excel 365 to fix.
• Pivot tables lose source data link — if your .xlsb had external Power Query or ODBC connections, the .xlsx may lose them. Re-establish connections after conversion.

FAQ

Q: Is converting .xlsb to .xlsx lossless?
A: Yes — when using Method 1 (Excel) or Method 3 (VBA, which uses Excel under the hood). Methods 2/4/5 are essentially lossless for typical office workbooks but may lose advanced features like Power Query connections or proprietary chart types.

Q: Why is the .xlsx file larger than the .xlsb?
A: .xlsb stores data in binary; .xlsx zips XML. Same data, different encoding. .xlsx files for the same workbook are typically 1.5-2x larger.

Q: Can I convert .xlsx back to .xlsb?
A: Yes — the process is reversible. Use our XLSX to XLSB converter or Excel's File > Save As > Excel Binary Workbook.

Q: Will conversion work on Mac Excel?
A: Yes, but Excel for Mac is notably slower with .xlsb files. On Mac, our online converter is often faster than waiting for Excel for Mac to even open the .xlsb.

Q: Are .xlsb files backwards compatible with Excel 2003?
A: No. .xlsb requires Excel 2007 or later. If your colleague has Excel 2003, convert to the older .xls format instead — use our XLSB to XLS converter.

Q: Can I do this entirely in Google Sheets?
A: No — Google Sheets cannot open .xlsb files directly. Convert to .xlsx first using any method above, then upload the .xlsx to Drive.

Bottom Line

For 95% of users converting a single .xlsb file with formulas and charts intact, Method 2 (our free online converter) is the fastest path — no Excel required, 3 seconds per file, and the output matches what Excel produces.

For batch jobs across hundreds of files, Method 3 (VBA macro) wins — free, fast, and 100% lossless when saved as .xlsm.

For data pipelines and headless servers, Method 4 (Python pandas) is the right choice — even though it loses formatting, you usually only care about the data values in that context.

Need more flexibility? ExcelMaster is the AI agent inside Excel that handles file conversion, formula generation, VBA writing, and Python automation in one tool — free trial, no signup required for the converter itself.