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C# Export to Excel: Complete Developer Guide

Jacob Mellor

Updated:July 28, 2025

Working with Excel data often requires exporting spreadsheets to different formats for integration with various systems and applications. This guide demonstrates how to export Excel files to multiple formats including .xlsx, .xls, .csv, .xml, and .json using C# and IronXL—without requiring Microsoft Office Interop dependencies.

Step 1

How to Install IronXL for Excel Export?

IronXL provides a streamlined approach to working with Excel files in .NET applications. Download the IronXL DLL directly or install via NuGet for development and testing.

Install-Package IronXL.Excel

After installation, add the IronXL reference to access all Excel manipulation features through the IronXL namespace. The library supports .NET Framework, .NET Core, and .NET 5+ applications, making it compatible with modern development environments.

How to Tutorial

What Excel Export Formats Does C# Support?

IronXL enables seamless data export from Excel workbooks to multiple file formats. The library supports exporting to:

• Excel formats: .xlsx (modern) and .xls (legacy)
• Data interchange formats: .csv, .json, and .xml
• Tab-separated values: .tsv

Each format serves specific use cases—CSV for database imports, JSON for web APIs, and XML for enterprise system integration. Let's explore how to implement each export type.

How to Export Excel to XLSX in C#?

Converting between Excel formats is straightforward with IronXL. The following example demonstrates loading an older .xls file and saving it as a modern .xlsx file:

using IronXL;

namespace ExcelExportExample
{
    class Program
    {
        static void Main()
        {
            // Load an existing .xls workbook
            WorkBook workbook = WorkBook.Load("XlsFile.xls");

            // Save as modern .xlsx format
            workbook.SaveAs("newFile.xlsx");

            // Custom path example
            // workbook.SaveAs(@"E:\ExcelExports\ModernFormat.xlsx");
        }
    }
}

using IronXL;

namespace ExcelExportExample
{
    class Program
    {
        static void Main()
        {
            // Load an existing .xls workbook
            WorkBook workbook = WorkBook.Load("XlsFile.xls");

            // Save as modern .xlsx format
            workbook.SaveAs("newFile.xlsx");

            // Custom path example
            // workbook.SaveAs(@"E:\ExcelExports\ModernFormat.xlsx");
        }
    }
}

Imports IronXL

Namespace ExcelExportExample
	Friend Class Program
		Shared Sub Main()
			' Load an existing .xls workbook
			Dim workbook As WorkBook = WorkBook.Load("XlsFile.xls")

			' Save as modern .xlsx format
			workbook.SaveAs("newFile.xlsx")

			' Custom path example
			' workbook.SaveAs(@"E:\ExcelExports\ModernFormat.xlsx");
		End Sub
	End Class
End Namespace

The SaveAs method automatically detects the desired format based on the file extension. When converting from .xls to .xlsx, the process preserves all worksheets, formulas, formatting, and data types. This conversion is particularly useful when modernizing legacy Excel files for compatibility with newer Office versions.

How to Export Excel to XLS Format?

Legacy systems sometimes require the older .xls format. IronXL handles this conversion seamlessly:

using IronXL;

namespace XlsExportExample
{
    class Program
    {
        static void Main()
        {
            // Load a modern .xlsx workbook
            WorkBook workbook = WorkBook.Load("XlsxFile.xlsx");

            // Export to legacy .xls format
            workbook.SaveAs("legacyFormat.xls");
        }
    }
}

using IronXL;

namespace XlsExportExample
{
    class Program
    {
        static void Main()
        {
            // Load a modern .xlsx workbook
            WorkBook workbook = WorkBook.Load("XlsxFile.xlsx");

            // Export to legacy .xls format
            workbook.SaveAs("legacyFormat.xls");
        }
    }
}

Imports IronXL

Namespace XlsExportExample
	Friend Class Program
		Shared Sub Main()
			' Load a modern .xlsx workbook
			Dim workbook As WorkBook = WorkBook.Load("XlsxFile.xlsx")

			' Export to legacy .xls format
			workbook.SaveAs("legacyFormat.xls")
		End Sub
	End Class
End Namespace

This conversion maintains compatibility with Excel 97-2003 versions. The SaveAs method handles the format conversion internally, ensuring data integrity while adapting to the .xls format limitations such as the 65,536 row limit per worksheet.

How to Convert Excel to CSV in C#?

CSV export is essential for data exchange between different systems. IronXL provides a dedicated method for CSV conversion:

using IronXL;

namespace CsvExportExample
{
    class Program
    {
        static void Main()
        {
            // Load Excel workbook (supports .xlsx, .xls, .xlsm)
            WorkBook workbook = WorkBook.Load("sample.xlsx");

            // Export all worksheets to CSV files
            workbook.SaveAsCsv("exportedData.csv");

            // Optional: Specify custom delimiter
            // workbook.SaveAsCsv("exportedData.csv", ",");
        }
    }
}

using IronXL;

namespace CsvExportExample
{
    class Program
    {
        static void Main()
        {
            // Load Excel workbook (supports .xlsx, .xls, .xlsm)
            WorkBook workbook = WorkBook.Load("sample.xlsx");

            // Export all worksheets to CSV files
            workbook.SaveAsCsv("exportedData.csv");

            // Optional: Specify custom delimiter
            // workbook.SaveAsCsv("exportedData.csv", ",");
        }
    }
}

Imports IronXL

Namespace CsvExportExample
	Friend Class Program
		Shared Sub Main()
			' Load Excel workbook (supports .xlsx, .xls, .xlsm)
			Dim workbook As WorkBook = WorkBook.Load("sample.xlsx")

			' Export all worksheets to CSV files
			workbook.SaveAsCsv("exportedData.csv")

			' Optional: Specify custom delimiter
			' workbook.SaveAsCsv("exportedData.csv", ",");
		End Sub
	End Class
End Namespace

When exporting multi-sheet workbooks, IronXL creates separate CSV files for each worksheet. For a workbook with three sheets named "Sheet1", "Sheet2", and "Sheet3", the export generates:

Multiple CSV files generated from a three-sheet Excel workbook, with each worksheet exported as a separate CSV file

The original Excel file structure with three worksheets:

Original Excel workbook displaying three worksheets that will be exported as individual CSV files

The SaveAsCsv method preserves data values while removing formatting, formulas, and other Excel-specific features. This makes CSV ideal for importing data into databases or processing with other applications.

How to Export Excel Data to XML?

XML export enables structured data exchange with enterprise systems. IronXL simplifies this process:

using IronXL;

namespace XmlExportExample
{
    class Program
    {
        static void Main()
        {
            // Load Excel workbook
            WorkBook workbook = WorkBook.Load("sample.xlsx");

            // Export all worksheets to XML format
            workbook.SaveAsXml("dataExport.xml");
        }
    }
}

using IronXL;

namespace XmlExportExample
{
    class Program
    {
        static void Main()
        {
            // Load Excel workbook
            WorkBook workbook = WorkBook.Load("sample.xlsx");

            // Export all worksheets to XML format
            workbook.SaveAsXml("dataExport.xml");
        }
    }
}

Imports IronXL

Namespace XmlExportExample
	Friend Class Program
		Shared Sub Main()
			' Load Excel workbook
			Dim workbook As WorkBook = WorkBook.Load("sample.xlsx")

			' Export all worksheets to XML format
			workbook.SaveAsXml("dataExport.xml")
		End Sub
	End Class
End Namespace

The SaveAsXml method converts each worksheet into a separate XML file with a structured representation of the spreadsheet data. This includes:

• Cell values and data types
• Row and column positioning
• Basic structural information

XML export is particularly valuable for integrating Excel data with web services or systems that require structured data formats.

How to Generate JSON from Excel Files?

Modern web applications often require JSON format for data exchange. IronXL provides direct JSON export functionality:

using IronXL;

namespace JsonExportExample
{
    class Program
    {
        static void Main()
        {
            // Load Excel workbook
            WorkBook workbook = WorkBook.Load("sample.xlsx");

            // Export worksheets to JSON format
            workbook.SaveAsJson("dataExport.json");
        }
    }
}

using IronXL;

namespace JsonExportExample
{
    class Program
    {
        static void Main()
        {
            // Load Excel workbook
            WorkBook workbook = WorkBook.Load("sample.xlsx");

            // Export worksheets to JSON format
            workbook.SaveAsJson("dataExport.json");
        }
    }
}

Imports IronXL

Namespace JsonExportExample
	Friend Class Program
		Shared Sub Main()
			' Load Excel workbook
			Dim workbook As WorkBook = WorkBook.Load("sample.xlsx")

			' Export worksheets to JSON format
			workbook.SaveAsJson("dataExport.json")
		End Sub
	End Class
End Namespace

The SaveAsJson method creates JSON files with array-based structures representing spreadsheet data. Each worksheet exports as a separate JSON file, making it easy to:

• Integrate with RESTful APIs
• Process data in JavaScript applications
• Store spreadsheet data in NoSQL databases

For advanced scenarios, developers can combine JSON export with IronXL's data manipulation features to transform data before exporting.

Tutorial Quick Access

API Reference Documentation

Explore the complete IronXL API including all namespaces, classes, methods, and properties for advanced Excel manipulation.

View API Reference

Ready to Export Excel Files?

IronXL simplifies Excel file export operations in C# applications. Whether converting between Excel formats or exporting to data interchange formats like CSV, JSON, or XML, the library provides intuitive methods that handle complex conversions automatically.

Start implementing Excel export functionality today with a free trial of IronXL. For production deployments, explore our flexible licensing options designed for teams of all sizes.

Get stated with IronXL now.

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Jacob Mellor

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Chief Technology Officer

Jacob Mellor is Chief Technology Officer at Iron Software and a visionary engineer pioneering C# PDF technology. As the original developer behind Iron Software's core codebase, he has shaped the company's product architecture since its inception, transforming it alongside CEO Cameron Rimington into a 50+ person company serving NASA, Tesla, and global government agencies.

Jacob holds a First-Class Honours Bachelor of Engineering (BEng) in Civil Engineering from the University of Manchester (1998–2001). After opening his first software business in London in 1999 and creating his first .NET components in 2005, he specialized in solving complex problems across the Microsoft ecosystem.

His flagship IronPDF & IronSuite .NET libraries have achieved over 30 million NuGet installations globally, with his foundational code continuing to power developer tools used worldwide. With 25 years of commercial experience and 41 years of coding expertise, Jacob remains focused on driving innovation in enterprise-grade C#, Java, and Python PDF technologies while mentoring the next generation of technical leaders.

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