File Size Limits

Updated: April 22, 2026

Are file sizes limited in IronXL?

There is no file size or row/column limit in IronXL.

If you see an error message regarding 65,535 rows like below, it suggests that you are using a 1997-2003 version XLS file.

This workbook contains data in cells outside of the row and column limit of the selected file format. Data beyond 256 (IV) columns by 65,536 rows will not be saved. Formula references to data in this region will return a #REF! error.

This workbook contains data in cells outside of the row and column limit of the selected file format. Data beyond 256 (IV) columns by 65,536 rows will not be saved. Formula references to data in this region will return a #REF! error.

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The newer 2007-2010 XLS and XLSX version files have much higher limits.

Please see: Excel specifications and limits

Curtis Chau

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Technical Writer

Curtis Chau holds a Bachelor’s degree in Computer Science (Carleton University) and specializes in front-end development with expertise in Node.js, TypeScript, JavaScript, and React. Passionate about crafting intuitive and aesthetically pleasing user interfaces, Curtis enjoys working with modern frameworks and creating well-structured, visually appealing manuals.

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