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How to Merge or Split PDFs

Merging multiple PDF files into one can be highly useful in various scenarios. For instance, you can consolidate similar documents such as resumes into a single file instead of sharing multiple files. This article guides you through the process of merging multiple PDF files using C#. IronPDF simplifies PDF splitting and merging with intuitive method calls within your C# application. Below, we'll walk you through all the page manipulation functionalities.

How to Merge and Split PDF Pages in C#

How to Merge and Split PDF Pages in C#
  1. Download C# library to merge and split PDF document
  2. Load existing or create a PDF from HTML string, file or URL
  3. Merge two PDF files in C# with Merge method
  4. Split a PDF file by pages utilizing the CopyPage and CopyPages methods
  5. Save the PDF document to desired location


C# NuGet Library for PDF

Install with NuGet

Install-Package IronPdf
nuget.org/packages/IronPdf/
or
Java PDF JAR

Download DLL

Download DLL

Manually install into your project

Merge PDFs Example

In the following demonstration, we will initialize two two-paged HTML strings, render them as separate PDFs IronPDF, and then merge them:

:path=/static-assets/pdf/content-code-examples/how-to/merge-or-split-pdfs-merge.cs
using IronPdf;

// Two paged PDF
const string html_a =
    @"<p> [PDF_A] </p>
    <p> [PDF_A] 1st Page </p>
    <div style = 'page-break-after: always;' ></div>
    <p> [PDF_A] 2nd Page</p>";

// Two paged PDF
const string html_b =
    @"<p> [PDF_B] </p>
    <p> [PDF_B] 1st Page </p>
    <div style = 'page-break-after: always;' ></div>
    <p> [PDF_B] 2nd Page</p>";

var renderer = new ChromePdfRenderer();

var pdfdoc_a = renderer.RenderHtmlAsPdf(html_a);
var pdfdoc_b = renderer.RenderHtmlAsPdf(html_b);

// Four paged PDF
var merged = PdfDocument.Merge(pdfdoc_a, pdfdoc_b);
merged.SaveAs("Merged.pdf");
Imports IronPdf

' Two paged PDF
Private Const html_a As String = "<p> [PDF_A] </p>
    <p> [PDF_A] 1st Page </p>
    <div style = 'page-break-after: always;' ></div>
    <p> [PDF_A] 2nd Page</p>"

' Two paged PDF
Private Const html_b As String = "<p> [PDF_B] </p>
    <p> [PDF_B] 1st Page </p>
    <div style = 'page-break-after: always;' ></div>
    <p> [PDF_B] 2nd Page</p>"

Private renderer = New ChromePdfRenderer()

Private pdfdoc_a = renderer.RenderHtmlAsPdf(html_a)
Private pdfdoc_b = renderer.RenderHtmlAsPdf(html_b)

' Four paged PDF
Private merged = PdfDocument.Merge(pdfdoc_a, pdfdoc_b)
merged.SaveAs("Merged.pdf")
VB   C#

Result

This is the file that the code produced:

Split PDF Example

In the following demonstration, we will split the multi-pages PDF document from the previous example.

:path=/static-assets/pdf/content-code-examples/how-to/merge-or-split-pdfs-split.cs
using IronPdf;

// We will use the 4-page PDF from the Merge example above:
var pdf = PdfDocument.FromFile("Merged.pdf");

// Takes only the first page into a new PDF
var page1doc = pdf.CopyPage(0);
page1doc.SaveAs("Page1Only.pdf");

// Take the pages 2 & 3 (Note: index starts at 0)
var page23doc = pdf.CopyPages(1, 2);
page23doc.SaveAs("Pages2to3.pdf");
Imports IronPdf

' We will use the 4-page PDF from the Merge example above:
Private pdf = PdfDocument.FromFile("Merged.pdf")

' Takes only the first page into a new PDF
Private page1doc = pdf.CopyPage(0)
page1doc.SaveAs("Page1Only.pdf")

' Take the pages 2 & 3 (Note: index starts at 0)
Dim page23doc = pdf.CopyPages(1, 2)
page23doc.SaveAs("Pages2to3.pdf")
VB   C#

So this code saves two files:

  • Page1Only.pdf (Only the first page)
  • Pages2to3.pdf (Second to Third page)

Results

These are the two files produced:

Page1Only.pdf

Pages2to3.pdf