Excel spreadsheets are a ubiquitous tool for data management, analysis, and reporting. Whether you’re a business professional, a data analyst, or a software developer, there comes a time when you need to create customized Excel files to suit your specific needs. If you’re working with C#, you’re in luck because the FileFormat.Cells library offers very smart features to help you achieve precisely that. In this blog post, we’ll explore how to use FileFormat.Cells to customize Excel spreadsheet styles in C#.

We will conver the following topics in this blog post:

What is FileFormat.Cells?

Before we dive into the details, let’s briefly introduce FileFormat.Cells. It’s a C# library that allows you to work with Excel files programmatically. This library provides a comprehensive set of features for Excel file creation and manipulation, making it a valuable asset for developers looking to automate Excel-related tasks.

C# Excel API Installation

Prerequisites: Please make sure you have installed .NET Framework on your environment. This is the only thing you need to have installed before installing this FileFormat.Cells for spreadsheet automation.

Well, there are two ways to install this free Excel XLSX API. First, you can download the NuGet package. Second, by running the following command in the NuGet Package Manager:

Install-Package FileFormat.Cells

Open-source Spreadsheet Generator – Feature Exploration

After a successful installation, you can start using the functionalities offered by FileFormat.Cells. Since it is an open-source C# Excel API, you can extend its features stack as per your business requirements. So, the current version of FileFormat.Cells is 23.10.0 and it offers various features and some of them are listed below:

  • Users can create an empty Excel XLSX Workbook and add as many worksheets as need. Please see below code example for adding worksheets in the workbook.

  • FileFormat.Cells provides seamless feature to insert value to different cells. Please see below code example for adding values into different cells.

  • This C# Excel API exposes methods to load spreadsheets and returns the information about the Worksheet’s data such as images, text data, etc.

Real-World Use Case Example

Customizing Excel spreadsheet styles using FileFormat.Cells can be immensely useful in various scenarios. Copy and paste the following code snippet into your main file and run the program.


In this blog post, we’ve seen how to customize Excel spreadsheet styles in C# using FileFormat.Cells. This library provides simple and easy way to create Excel files that meet your exact requirements. Whether you’re looking to retrieve data from an existing workbook, or insert data into workbook or style and customize data, FileFormat.Cells can help you achieve your goals efficiently.

Explore the documentation and experiment with the library to unlock its full potential in your Excel-related projects. With a bit of creativity, you can design Excel files that are not only functional but also visually appealing and informative.

Start customizing your Excel spreadsheet styles in C# with FileFormat.Cells and take your data management to the next level!


As FileFormat.Cells for .NET stands as an open-source venture, accessible via GitHub, community contributions are sincerely welcomed and greatly valued.

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How to create a new MS Excel Spreadsheet File in C#?

Please follow this link to learn MS Excel Spreadsheet file creation programmatically using this open-source spreadsheet automation software FileFormat.Cells.