How to Render PDFs with Custom Paper Size

by Chaknith Bin

A custom watermark is a personalized image or text overlay added to a PDF. It serves various purposes, including branding with logos or names, enhancing security with labels like 'Confidential,' ensuring copyright protection, and indicating document status. Custom watermarks can include text, images, or both, be applied selectively or universally, and their opacity can be adjusted for versatility in personalizing, securing, and contextualizing PDFs.

IronPdf offers a one-liner to apply a watermark. The watermark feature accepts a HTML string to generate the watermark, which is capable of using all HTML features as well as CSS styling.

C# NuGet Library for PDF

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Install-Package IronPdf

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Manually install into your project

Use Custom Paper Size Example

First, we begin by instantiating the ChromePdfRenderer class. From the newly created object, we can access the RenderingOptions to apply a custom paper size to the newly generated PDF document. There are four methods that can be used to set the output paper size for PDF pages, each based on a different measurement unit:

  • SetCustomPaperSizeInCentimeters: Dimensions are in centimeters.
  • SetCustomPaperSizeInInches: Dimensions are in inches.
  • SetCustomPaperSizeInMillimeters: Dimensions are in millimeters.
  • SetCustomPaperSizeInPixelsOrPoints: Dimensions are in pixels or points.


using IronPdf;

ChromePdfRenderer renderer = new ChromePdfRenderer();

// Set custom paper size in cm
renderer.RenderingOptions.SetCustomPaperSizeinCentimeters(15, 15);

PdfDocument pdf = renderer.RenderHtmlAsPdf("<h1>Custom Paper Size</h1>");

Imports IronPdf

Private renderer As New ChromePdfRenderer()

' Set custom paper size in cm
renderer.RenderingOptions.SetCustomPaperSizeinCentimeters(15, 15)

Dim pdf As PdfDocument = renderer.RenderHtmlAsPdf("<h1>Custom Paper Size</h1>")

VB   C#

Output PDF

Chaknith Bin

Software Engineer

Chaknith is the Sherlock Holmes of developers. It first occurred to him he might have a future in software engineering, when he was doing code challenges for fun. His focus is on IronXL and IronBarcode, but he takes pride in helping customers with every product. Chaknith leverages his knowledge from talking directly with customers, to help further improve the products themselves. His anecdotal feedback goes beyond Jira tickets and supports product development, documentation and marketing, to improve customer’s overall experience.When he isn’t in the office, he can be found learning about machine learning, coding and hiking.