HTML to PDF C#: using IronPDF

Introduction

PDF (Portable Document Format) is one of the most widely used file formats for sharing and preserving documents. It ensures that documents maintain their formatting, fonts, and structure across different devices and operating systems. Businesses, developers, and content creators often need to generate a PDF format for documents dynamically, whether for reports, invoices, or online receipts.

Converting an HTML document to PDF is particularly important because web technologies are dominant in content generation. Websites, dashboards, and reports often rely on HTML, CSS, and JavaScript for rich presentation. Transforming such content into a PDF file enables easy sharing, printing, and archiving while retaining the document's layout and interactivity.

HTML to PDF conversion in C# .NET has been a long-debated topic, with new libraries continuously emerging to offer better performance, accuracy, and ease of use. In this article, we will create an HTML to PDF converter application in C# using IronPDF, enabling the conversion of HTML strings, URLs, and HTML files to PDF.

How to Convert HTML to PDF in C#

1. Start by creating a new C# Console or Web Application in Visual Studio.
2. Add the C# PDF library to your project using the NuGet Package Manager.
3. Convert an HTML string into a PDF document using the RenderHtmlAsPdf method.
4. Load an external HTML file and convert it into a PDF using RenderHTMLFileAsPdf.
5. Capture and convert live web pages into PDF documents using RenderUrlAsPdf.
6. Save the generated PDF document to disk using the SaveAs method.

IronPDF - The C# PDF Library

IronPDF is a powerful C# library designed to handle PDF generation, manipulation, and conversion with ease. One of its most popular features is HTML-to-PDF conversion, which allows developers to create high-quality PDFs from HTML strings, web pages, or existing HTML files. It seamlessly integrates with .NET applications and provides developers with an easy-to-use API for PDF creation and processing.

Unlike other libraries that require complex setup or external dependencies, IronPDF includes a built-in Chromium-based rendering engine. This ensures that the converted PDF maintains accurate styling, font rendering, and JavaScript execution, making it a reliable choice for web-to-PDF conversion.

Key Features of IronPDF

• Convert HTML to PDF – Generate PDFs from HTML strings, web pages, or local HTML files.
• Full HTML5 & CSS3 Support – Ensure accurate rendering with support for modern web standards.
• JavaScript Execution – Convert dynamically generated content that relies on JavaScript.
• Customizable Headers & Footers – Add page numbers, timestamps, and custom branding to PDF files.
• Security Features – Encrypt PDFs with passwords and permissions.
• Merge & Edit PDFs – Combine multiple PDFs and manipulate pages programmatically.

Prerequisites

Before starting, ensure you have the following:

• Visual Studio (2019 or later) – Download from Microsoft Visual Studio.
• .NET Framework (.NET Core or .NET 6/7/8) – Install from Microsoft .NET.
• IronPDF NuGet package – Available via NuGet Package Manager.

Steps to Create a Visual Studio Project

1. Open Visual Studio and create a new C# Console Application.
2. Name the project HTMLToPDFDemo and click Create.
3. Choose .NET Core or .NET Framework, depending on your preference.

Installing IronPDF via NuGet Package Manager

To install IronPDF, follow these steps:

1. Open NuGet Package Manager in Visual Studio.
2. Search for IronPDF.
3. Click Install and wait for the installation to complete.

Alternatively, you can install it using the Package Manager Console by running:

PM> NuGet\Install-Package IronPdf -Version 2025.2.8        

Importing IronPDF and Setting the License Key

Before using IronPDF, you need to import the library and set the license key:

using IronPdf;

License.LicenseKey = "YOUR_LICENSE_KEY";        

Setting the license key ensures you have access to all features without limitations. You can obtain a license key or your trial license from the IronPDF website. Alternatively, you can set the license key via an environment variable:

Environment.SetEnvironmentVariable("IRONPDF_LICENSE_KEY", "YOUR_LICENSE_KEY");        

Converting HTML to PDF Using IronPDF Library

1. Convert HTML String to PDF

You can generate a PDF from an HTML string as follows:

using IronPdf;

var Renderer = new ChromePdfRenderer();
var pdf = Renderer.RenderHtmlAsPdf("<h1>Hello, IronPDF!</h1><p>This is a sample HTML to PDF conversion.</p>");
pdf.SaveAs("output.pdf");        

This method directly converts a raw HTML string into a PDF document. It is useful for generating reports, invoices, or other documents where the HTML content is dynamically generated within the application. IronPDF accurately renders the HTML structure, including styles and inline CSS.

Output PDF

2. Convert an HTML File to PDF

If you have an HTML file, the following code will help you easily convert HTML File to a PDF using:

var Renderer = new ChromePdfRenderer();
var pdf = Renderer.RenderHtmlFileAsPdf("sample.html");
pdf.SaveAs("output.pdf");        

This method help to convert HTML files to PDF by reading its contents efficiently. It is particularly useful for applications that generate HTML-based reports or documents that need to be stored as PDFs. The method preserves the file and html page's layout, including fonts, images, and CSS styles.

Following code snippet is from the sample.html file:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Sample HTML</title>
    <style>
        body {
            font-family: Arial, sans-serif;
            margin: 20px;
            padding: 20px;
            border: 1px solid #ddd;
        }
        h1 {
            color: #2c3e50;
        }
        p {
            font-size: 16px;
            color: #555;
        }
    </style>
</head>
<body>
    <h1>Welcome to IronPDF</h1>
    <p>This is a sample HTML file that will be converted into a PDF using IronPDF.</p>
</body>
</html>        

Output PDF

3. Convert a URL to PDF

You can also convert a live webpage to a PDF document. The following code snippet helps to convert the URL content to PDF:

var Renderer = new ChromePdfRenderer();
var pdf = Renderer.RenderUrlAsPdf("https://ironpdf.com");
pdf.SaveAs("output.pdf");        

This method fetches a webpage from a given URL and converts it into a PDF. It is useful for archiving web pages, capturing dynamic reports, or saving website content as a PDF. IronPDF ensures that even JavaScript-rendered content is properly included to create pdfs.

Output PDF

For more detailed information on HTML to PDF, please visit the documentation and HTML to PDF tutorial.

Conclusion

IronPDF simplifies HTML-to-PDF conversion in C# by providing an intuitive API, full support for modern web standards, and built-in Chromium rendering. Whether you're working with HTML strings, local files, or online web pages, IronPDF ensures accurate and high-quality PDF generation. By following the steps above, developers can seamlessly integrate the PDF rendering and generation into their .NET applications and enhance their document processing capabilities.

IronPDF offers a free trial to test out its full functionality before making a commitment. For more licensing options please visit this page. Download IronPDF from here and try it out!