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How to Split PDF Files in C# (.NET Guide)

#dotnet #csharp

Splitting PDFs means breaking one document into multiple files. Extract individual pages, create page ranges, or divide a 100-page report into 10-page chunks for easier distribution.

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("large-document.pdf");

// Extract pages 1-5 (indices 0-4)
var firstSection = pdf.CopyPages(0, 4);
firstSection.SaveAs("section-1.pdf");

// Extract pages 6-10 (indices 5-9)
var secondSection = pdf.CopyPages(5, 9);
secondSection.SaveAs("section-2.pdf");
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IronPDF's CopyPages method extracts pages into new documents without modifying the original.

How Do I Split Into Single-Page Files?

Create individual files for each page:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("multipage-document.pdf");

for (int i = 0; i < pdf.PageCount; i++)
{
    var singlePage = pdf.CopyPage(i);
    singlePage.SaveAs($"page-{i + 1}.pdf");
    singlePage.Dispose();
}

Console.WriteLine($"Split into {pdf.PageCount} individual files");
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Each page becomes its own PDF file.

How Do I Extract a Page Range?

Get a specific section from a larger document:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("annual-report.pdf");

// Extract chapters (page numbers, 0-indexed)
var intro = pdf.CopyPages(0, 2);      // Pages 1-3
intro.SaveAs("introduction.pdf");

var analysis = pdf.CopyPages(3, 15);   // Pages 4-16
analysis.SaveAs("analysis.pdf");

var appendix = pdf.CopyPages(16, pdf.PageCount - 1);  // Rest
appendix.SaveAs("appendix.pdf");
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How Do I Split by Fixed Page Count?

Divide into equal-sized chunks:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

public void SplitByPageCount(string inputPath, int pagesPerFile, string outputFolder)
{
    var pdf = PdfDocument.FromFile(inputPath);
    int totalPages = pdf.PageCount;
    int fileIndex = 1;

    for (int start = 0; start < totalPages; start += pagesPerFile)
    {
        int end = Math.Min(start + pagesPerFile - 1, totalPages - 1);
        var section = pdf.CopyPages(start, end);

        var outputPath = Path.Combine(outputFolder, $"part-{fileIndex}.pdf");
        section.SaveAs(outputPath);
        section.Dispose();

        Console.WriteLine($"Created: part-{fileIndex}.pdf (pages {start + 1}-{end + 1})");
        fileIndex++;
    }

    pdf.Dispose();
}

// Usage: Split into 10-page chunks
SplitByPageCount("large-report.pdf", 10, "C:/Output");
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A 45-page document becomes 5 files: four with 10 pages, one with 5.

How Do I Extract Specific Pages?

Pick non-consecutive pages:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("document.pdf");

// Extract pages 1, 5, 10, 15 (0-indexed: 0, 4, 9, 14)
int[] pagesToExtract = { 0, 4, 9, 14 };

var extracted = PdfDocument.FromFile("document.pdf").CopyPage(pagesToExtract[0]);

for (int i = 1; i < pagesToExtract.Length; i++)
{
    var page = pdf.CopyPage(pagesToExtract[i]);
    extracted = PdfDocument.Merge(extracted, page);
}

extracted.SaveAs("selected-pages.pdf");
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How Do I Remove Pages from a PDF?

Remove unwanted pages by keeping the rest:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("document.pdf");

// Remove page 3 (index 2)
pdf.RemovePage(2);

// Remove multiple pages (remove from end to preserve indices)
int[] pagesToRemove = { 10, 7, 3 };  // Sorted descending
foreach (int pageIndex in pagesToRemove.OrderByDescending(p => p))
{
    pdf.RemovePage(pageIndex);
}

pdf.SaveAs("trimmed-document.pdf");
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Remove from highest index first to avoid shifting issues.

How Do I Split Even and Odd Pages?

Separate for duplex printing:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

public void SplitEvenOdd(string inputPath)
{
    var pdf = PdfDocument.FromFile(inputPath);

    var oddPages = new List<int>();
    var evenPages = new List<int>();

    for (int i = 0; i < pdf.PageCount; i++)
    {
        if ((i + 1) % 2 == 1)  // Page numbers are 1-based
            oddPages.Add(i);
        else
            evenPages.Add(i);
    }

    // Create odd pages document
    if (oddPages.Count > 0)
    {
        var oddDoc = pdf.CopyPage(oddPages[0]);
        for (int i = 1; i < oddPages.Count; i++)
        {
            var page = pdf.CopyPage(oddPages[i]);
            oddDoc = PdfDocument.Merge(oddDoc, page);
        }
        oddDoc.SaveAs("odd-pages.pdf");
    }

    // Create even pages document
    if (evenPages.Count > 0)
    {
        var evenDoc = pdf.CopyPage(evenPages[0]);
        for (int i = 1; i < evenPages.Count; i++)
        {
            var page = pdf.CopyPage(evenPages[i]);
            evenDoc = PdfDocument.Merge(evenDoc, page);
        }
        evenDoc.SaveAs("even-pages.pdf");
    }
}
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How Do I Split Based on File Size?

Create files under a size limit:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

public void SplitBySize(string inputPath, long maxSizeBytes, string outputFolder)
{
    var pdf = PdfDocument.FromFile(inputPath);
    int fileIndex = 1;
    int startPage = 0;

    while (startPage < pdf.PageCount)
    {
        var section = pdf.CopyPage(startPage);
        int endPage = startPage;

        // Keep adding pages until size limit approached
        while (endPage + 1 < pdf.PageCount)
        {
            var nextPage = pdf.CopyPage(endPage + 1);
            var testMerge = PdfDocument.Merge(section, nextPage);

            if (testMerge.BinaryData.Length > maxSizeBytes)
            {
                testMerge.Dispose();
                break;
            }

            section = testMerge;
            endPage++;
        }

        var outputPath = Path.Combine(outputFolder, $"part-{fileIndex}.pdf");
        section.SaveAs(outputPath);
        Console.WriteLine($"Created: part-{fileIndex}.pdf ({section.BinaryData.Length / 1024} KB)");

        section.Dispose();
        startPage = endPage + 1;
        fileIndex++;
    }
}

// Usage: Split into files under 5MB
SplitBySize("huge-document.pdf", 5 * 1024 * 1024, "C:/Output");
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How Do I Extract the First/Last N Pages?

Common extraction patterns:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("document.pdf");

// First 5 pages
var firstFive = pdf.CopyPages(0, 4);
firstFive.SaveAs("first-five.pdf");

// Last 5 pages
int lastStart = Math.Max(0, pdf.PageCount - 5);
var lastFive = pdf.CopyPages(lastStart, pdf.PageCount - 1);
lastFive.SaveAs("last-five.pdf");

// Everything except first page (cover)
var withoutCover = pdf.CopyPages(1, pdf.PageCount - 1);
withoutCover.SaveAs("no-cover.pdf");

// Everything except last page
var withoutLast = pdf.CopyPages(0, pdf.PageCount - 2);
withoutLast.SaveAs("no-appendix.pdf");
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How Do I Batch Split Multiple PDFs?

Process an entire folder:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

public void BatchSplit(string inputFolder, string outputFolder, int pagesPerFile)
{
    var files = Directory.GetFiles(inputFolder, "*.pdf");

    foreach (var file in files)
    {
        var baseName = Path.GetFileNameWithoutExtension(file);
        var pdf = PdfDocument.FromFile(file);
        int partIndex = 1;

        for (int start = 0; start < pdf.PageCount; start += pagesPerFile)
        {
            int end = Math.Min(start + pagesPerFile - 1, pdf.PageCount - 1);
            var section = pdf.CopyPages(start, end);

            var outputPath = Path.Combine(outputFolder, $"{baseName}-part{partIndex}.pdf");
            section.SaveAs(outputPath);
            section.Dispose();

            partIndex++;
        }

        Console.WriteLine($"Split {baseName}: {partIndex - 1} parts");
        pdf.Dispose();
    }
}
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How Do I Split and Name by Content?

If you know page structure, name files meaningfully:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

public void SplitReport(string reportPath, string outputFolder)
{
    var pdf = PdfDocument.FromFile(reportPath);

    // Known structure: Cover (1), TOC (1), Intro (3), Body (varies), Appendix (5)
    var sections = new (string name, int startPage, int endPage)[]
    {
        ("cover", 0, 0),
        ("table-of-contents", 1, 1),
        ("introduction", 2, 4),
        ("main-content", 5, pdf.PageCount - 6),
        ("appendix", pdf.PageCount - 5, pdf.PageCount - 1)
    };

    foreach (var (name, start, end) in sections)
    {
        if (start <= end && end < pdf.PageCount)
        {
            var section = pdf.CopyPages(start, end);
            section.SaveAs(Path.Combine(outputFolder, $"{name}.pdf"));
            section.Dispose();
        }
    }
}
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Quick Reference

Operation Code
Copy single page pdf.CopyPage(pageIndex)
Copy page range pdf.CopyPages(startIndex, endIndex)
Remove page pdf.RemovePage(pageIndex)
Get page count pdf.PageCount
Merge PDFs PdfDocument.Merge(pdf1, pdf2)
Common Pattern Range (0-indexed)
First N pages 0 to N - 1
Last N pages PageCount - N to PageCount - 1
Pages X to Y X - 1 to Y - 1
Skip first page 1 to PageCount - 1

Remember: page indices are zero-based. Page 1 = index 0.

Splitting PDFs enables document management workflows—distribute sections to different teams, archive by chapter, or create email-friendly file sizes.

For more splitting options, see the IronPDF split documentation.

Written by Jacob Mellor, CTO at Iron Software. Jacob created IronPDF and leads a team of 50+ engineers building .NET document processing libraries.

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