XLSB Viewer — Open XLSB Files Online

Drop your .xlsb file here

or click to browse — supports .xlsb, .xlsx, .xls

100% client-side — your files never leave your browser

Open XLSB Files Online — No Excel Required

XLSB Viewer is a free online tool that lets you open, view, and convert XLSB files directly in your web browser. There is no need to install Microsoft Excel, LibreOffice, or any other desktop software. Simply drag and drop your file onto the page and your spreadsheet data appears instantly in a clean, sortable table.

Unlike other online converters, XLSB Viewer is powered by WebAssembly and Rust, which means all file processing happens directly on your device. Your files are never uploaded to any server. This makes it completely safe for confidential spreadsheets, financial data, and any sensitive business information.

Whether you received an XLSB file from a colleague, need to inspect legacy Excel data, or want to convert a spreadsheet into JSON for your application, XLSB Viewer handles it in seconds without leaving your browser tab.

What Is an XLSB File?

XLSB stands for Excel Binary Workbook. It is a Microsoft Excel file format that stores spreadsheet data in a compact binary structure rather than the XML-based format used by XLSX files. Because of this binary encoding, XLSB files are typically smaller and faster to open in Excel compared to their XLSX counterparts. They are commonly used in finance, insurance, and enterprise environments where spreadsheets contain hundreds of thousands of rows.

The downside is that XLSB files cannot be opened by most third-party tools. Google Sheets does not support them, and many programming libraries skip XLSB support entirely. XLSB Viewer solves this problem by using the calamine library compiled to WebAssembly, giving you native-speed parsing right in the browser.

Features

View Spreadsheets

Browse your XLSB data in a fast, paginated table with sortable columns, full-text search, and sticky headers. Handles files with millions of rows without slowing down.

Convert XLSB to JSON

Instantly convert your spreadsheet to JSON in three formats: records (array of objects), 2D array, or column-oriented. Copy to clipboard or download as a file with one click.

100% Private and Secure

All processing runs locally in your browser via WebAssembly. No server, no upload, no tracking, no cookies. Your data never leaves your device under any circumstances.

Multiple File Formats

Supports XLSB, XLSX, XLS, XLSM, and ODS files. One tool for all your spreadsheet viewing and conversion needs, regardless of the Excel version used to create the file.

Blazing Fast Performance

Built with Rust compiled to WebAssembly for near-native parsing speed. Large files that take minutes in other tools open in seconds here.

Multi-Sheet Support

Navigate between sheets with tab switching. Each sheet has independent search, sort, and pagination state so you can work with complex workbooks easily.

How to Open an XLSB File Online

  1. 1. Drop your file — Drag your .xlsb file onto the upload area at the top of this page, or click the area to open your file browser and select the file manually.
  2. 2. View your data — Your spreadsheet opens instantly in a sortable, searchable table. Use the pagination controls to browse through large datasets, and click column headers to sort ascending or descending.
  3. 3. Switch to JSON view — Click the Table / JSON toggle in the header bar to see your data as structured JSON. Pick your preferred format, then use Copy or Download to export.
  4. 4. Switch sheets — If your workbook has multiple sheets, click the sheet tabs below the header to navigate between them. Each sheet loads independently.

Common Use Cases

  • Inspecting XLSB files from colleagues — Quickly view spreadsheet data shared via email or file transfer without installing Excel on your machine.
  • Converting XLSB to JSON for developers — Export spreadsheet data as structured JSON for use in web applications, APIs, databases, or data pipelines.
  • Viewing legacy Excel files — Open old XLS and XLSB files created by earlier versions of Microsoft Excel that may not open correctly in newer software.
  • Data validation and spot-checking — Quickly check row counts, column names, and data types in a large spreadsheet before importing it into another system.
  • Working on Chromebooks or Linux — View Excel files on devices where Microsoft Office is not available and Google Sheets does not support the file format.

Frequently Asked Questions

How do I open an XLSB file without Excel?

Use XLSB Viewer — just drag and drop your .xlsb file into the browser. It opens instantly with no software installation required. The file is processed entirely in your browser using WebAssembly, so nothing is uploaded to any server.

How do I convert XLSB to JSON?

Upload your XLSB file to XLSB Viewer, then click the JSON toggle in the header. You can choose between three formats: records (array of objects), array (2D array), or columnar (column-oriented). Click Download to save the JSON file.

Is it safe to upload my XLSB file?

Yes. XLSB Viewer processes files 100% in your browser using WebAssembly. Your files are never uploaded to any server. All data stays on your device.

What is an XLSB file?

XLSB (Excel Binary Workbook) is a Microsoft Excel file format that stores spreadsheet data in binary format. It is faster to open and smaller than XLSX files, but requires specialized software to view. XLSB Viewer lets you open these files directly in your browser.

What file formats are supported?

XLSB Viewer supports XLSB (Excel Binary Workbook), XLSX (Excel), XLS (Legacy Excel), XLSM (Macro-Enabled Excel), and ODS (OpenDocument Spreadsheet) files.

Is there a file size limit?

There is no hard file size limit. Since processing happens in your browser, the limit depends on your device's available memory. Most devices can handle files up to several hundred megabytes without issues.

Can I use XLSB Viewer on mobile?

Yes. XLSB Viewer works on any device with a modern web browser, including phones and tablets. The interface is fully responsive.