The extension name of an MS Excel 2010 workbook is .xlsx by default.

Since you asked in a more “blog-style” format, here’s a quick, SEO-friendly “Quick Scoop” style answer.

What Is the Extension Name of MS Excel 2010?

Quick Scoop

When you create and save a normal workbook in Microsoft Excel 2010, it is saved with the .xlsx file extension. This is the modern XML-based Excel format introduced in Excel 2007 and continued in Excel 2010.

Mini Breakdown: Common Excel 2010 Extensions

Here are the main Excel 2010-related extensions you might see:

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File Type Extension What It’s For
Standard Excel 2010 workbook .xlsx Default format for regular spreadsheets without macros.
Macro- enabled workbook .xlsm Used when the workbook contains macros (VBA code).
Binary workbook .xlsb Binary format, often used for very large workbooks for performance.
Old Excel 97–2003 workbook .xls Legacy format used by older versions of Excel, still supported by Excel 2010.

Why .xlsx Matters Today

  • It’s based on the Office Open XML standard, which generally leads to smaller file sizes and better data recovery.
  • It’s the expected format for most modern Excel files shared in offices, schools, and online communities today.
  • Many tutorials, exam questions, and forum discussions still specifically ask: “What is the default file extension of Excel 2010?” — the answer they want is .xlsx.

In forum-style MCQs, if you see options like .xls, .xlsx, .xlsm, .excel, the correct one for “extension name of MS Excel 2010 file/default extension” is .xlsx.

TL;DR:
For “what is the extension name of MS Excel 2010” in exams, interviews, or forum quizzes, use .xlsx as the correct answer.

Information gathered from public forums or data available on the internet and portrayed here.