How much smaller will a file be if I save it as XLSB?

It depends on the data, but saving the same workbook as XLSB often significantly reduces its size compared with XLSX/XLSM and improves opening and saving speed.

Does XLSB support macros (VBA)?

Yes. XLSB supports storing and running macros. They may be blocked by security settings or trusted-location settings, so check the Trust Center settings.

Can I open an XLSB file directly in Google Sheets?

No. Google Sheets cannot open XLSB files directly. Convert the file to XLSX or CSV in Excel or another compatible application before uploading it.

What are the disadvantages or precautions of XLSB?

Some third-party tools may not support XLSB, and text-based diffs are difficult, so Open XML may be better for version control and auditing.

How do I set XLSB as the default save format?

Go to File > Options > Save, then select Excel Binary Workbook (*.xlsb) under 'Save files in this format.'

CONTENTS

How to Reduce Excel File Size: The Complete Guide to Saving as XLSB (Binary)

The key to reducing Excel file size is changing the save format. The most effective solution is saving as XLSB (binary). This article covers a Quick Fix you can apply in 10 seconds, why it reduces file size, a reproducible test you can follow for real-world work, plus additional optimization tips and precautions.

Quick Fix: Save as XLSB in 10 Seconds

File > Save As
Under Save as type, select Excel Binary Workbook (*.xlsb) → Save

To change the default: Go to File > Options > Save > Save files in this format, then select Excel Binary Workbook.

Why Does It Reduce File Size? (How XLSX and XLSB Work)

XLSX/XLSM: Open XML packages (collections of compressed XML parts)
XLSB: Stores the same content as binary records (BIFF12) → lower parsing and writing overhead, smaller file size
Note: XLSB can store and run macros (VBA).

Real-World Example: Compare Using the Same Data

Test Data (Reproduction Instructions)

Sample table: 100,000 rows × 5 columns (A:E)
Column A: 1–100000; columns B and C: random numbers; column D: =B*1.1; column E: =C*D
Data-entry tip: After entering a formula, press Ctrl + Enter to enter it into the selected range at once.

Save A: Save as XLSX. Save B: Save as XLSB. Then compare file size and opening/saving times.

7 More Ways to Reduce File Size

Compress pictures: Picture Format > Compress Pictures
Reset the used range (UsedRange): Delete unnecessary formatting, then check with Ctrl+End.
Clean up PivotTable and Data Model caches
Remove external connections: Data > Queries & Connections
Clean up defined names: Formulas > Name Manager
Remove hidden objects and worksheets
Store text/CSV files separately

When Should You Not Use XLSB? (Compatibility Check)

If you plan to open the file directly in Google Sheets → XLSB is not recommended (convert it first).
Some third-party tools do not support XLSB → test in advance.
If auditing or version control requires text-based comparisons, Open XML is recommended.

Troubleshooting

Issue	Possible Cause	Solution
File size does not decrease	Too many images/shapes or an oversized used range	Compress pictures and reset the used range
Saving is slow	External connections, queries, or PivotTable caches	Clean up connections/caches and remove the Data Model
A colleague cannot open the file	The tool does not support XLSB	Convert to XLSX/CSV
Macros do not run	Blocked by security settings	Configure trusted locations and macro settings in the Trust Center
Version-control diffs are inconvenient	Binary file format	Maintain key worksheets as CSV files as well

Excel worksheet shortcuts 총정리: 시트 이동·삽입·삭제·숨기기

How to Reduce Excel File Size: Save as XLSB for Faster Results