How to Compress PDF Files in Java

Curtis Chau

Updated: August 2, 2026

Download IronPDF

• Maven Central Download
• DLL Download

• ---

• Start Free Trial

Copy for LLMs

• Copy for LLMs

  Copy page as Markdown for LLMs
  # How to Compress PDF Files in Java IronPDF enables Java developers to compress PDF files by reducing image quality and scaling resolution, helping reduce file sizes for easier sharing and storage. *as-heading:2(Quickstart: Compress a PDF File in Java)* ```java {title="compress pdf in java"} import com.ironsoftware.ironpdf.*; import java.nio.file.Paths; // Load your PDF document PdfDocument pdf = PdfDocument.fromFile(Paths.get("source.pdf")); // Compress images to 60% quality pdf.compressImages(60); // Save the compressed PDF pdf.saveAs(Paths.get("compressed.pdf")); ``` <div class="hsg-featured-snippet"> <h3>Minimal Workflow (5 steps)</h3> <ol> <li>Add IronPDF to your Maven <code>pom.xml</code> as a dependency</li> <li>Load your PDF using <code>PdfDocument.fromFile()</code></li> <li>Compress images with <code>pdf.compressImages(60)</code></li> <li>Optionally scale image resolution with <code>pdf.compressImages(90, true)</code></li> <li>Save the compressed PDF using <code>pdf.saveAs()</code></li> </ol> </div> PDF documents are widely used for sharing and storing information, but image-heavy files can reach tens of megabytes very quickly. Large file sizes complicate email delivery, slow down uploads, and inflate storage costs. IronPDF's Java compression API addresses this by letting you reduce embedded image quality and scale resolution in a few lines of code. This article covers how to compress PDF files in Java using IronPDF. The examples show both simple quality-based compression and resolution scaling, so you can match the approach to your specific size and quality requirements. If you are also working with [image-heavy PDFs](https://ironpdf.com/java/how-to/java-pdf-to-image-tutorial/) or need to handle [merged documents](https://ironpdf.com/java/how-to/java-merge-pdf-tutorial/), compression is an essential step before distribution. ## What Is the IronPDF Java PDF Library? IronPDF is a [Java PDF library](/java/) that creates, reads, and manipulates PDF documents programmatically. The library handles [HTML to PDF conversion](https://ironpdf.com/java/tutorials/html-to-pdf/), form filling, image embedding, and file compression without requiring a PDF viewer or external rendering engine. It supports various deployment environments including [AWS Lambda](https://ironpdf.com/java/get-started/aws/), [Azure Functions](https://ironpdf.com/java/get-started/azure/), and [Google Cloud](https://ironpdf.com/java/get-started/google-cloud/). Compression in IronPDF works by resampling embedded images to a lower JPEG quality level and, optionally, reducing their resolution to match the display size in the PDF. Text, vector graphics, and document structure are not affected. This makes IronPDF a practical choice for large documents that need to be transferred quickly over email or stored in cloud-based systems. The library also works well alongside other document operations: you can compress a PDF that already has [watermarks](https://ironpdf.com/java/how-to/custom-watermark/), [background layers](https://ironpdf.com/java/how-to/background-foreground/), and [bookmarks](https://ironpdf.com/java/how-to/bookmarks/), and all those features are preserved after compression. [[i:(Compression is most effective on PDFs that contain embedded JPEG or PNG images. Documents made up mostly of text and vector graphics will see minimal size reduction.)]] ## How Do I Set Up IronPDF in a Java Maven Project? Before compressing PDFs, add IronPDF to your project's Maven configuration. For full setup instructions, see the [Get Started Overview](https://ironpdf.com/java/docs/). - To install IronPDF in a [Maven project](/java/docs/), add the `IronPDF` Maven repository and dependency to your `pom.xml` file. - Add the dependency to the `<dependencies>` section: ```xml <dependency> <groupId>com.ironsoftware</groupId> <artifactId>ironpdf</artifactId> <version>your_version_here</version> </dependency> ``` - Save your `pom.xml` and run `mvn install` to download the `IronPDF` dependency. Once the dependency resolves, you can import and use `IronPDF` classes in your project. The latest published version of the `IronPDF` Java artifact is available on [Maven Central](https://search.maven.org/artifact/com.ironsoftware/ironpdf). For production deployment, [configure your license key](https://ironpdf.com/java/get-started/license-keys/) before running. ## How Do I Compress a PDF File in Java? `IronPDF` compresses PDF files by targeting the embedded images inside the document. The `compressImages()` method accepts a quality integer from 0 to 100, where lower values produce smaller files at the cost of image sharpness. An optional second parameter instructs the library to scale down image resolution based on the display size in the PDF page. ```java import com.ironsoftware.ironpdf.*; import java.io.IOException; import java.nio.file.Paths; public class App { public static void main(String[] args) throws IOException { // Load the source PDF from disk String src = "C:\\Image based PDF.pdf"; PdfDocument pdf = PdfDocument.fromFile(Paths.get(src)); // First pass: compress images to 60% quality // Lower values produce smaller files with more visible quality loss pdf.compressImages(60); pdf.saveAs(Paths.get("assets/document_compressed.pdf")); // Second pass (optional): compress to 90% quality with resolution scaling // The second parameter scales image resolution down to match display size, // which can reduce file size further but may cause distortion in some PDFs pdf.compressImages(90, true); pdf.saveAs(Paths.get("C:\\Compressed.pdf")); } } ``` The code loads a PDF from disk and applies compression in two passes to illustrate different strategies. The first `compressImages(60)` call reduces image quality to 60% and saves the result. The second call uses 90% quality but enables resolution scaling, which adjusts each image's pixel dimensions to match its visible area on the page. The `compressImages()` method has two signatures: - **`compressImages(int quality)`**: Resamples all embedded images to the given JPEG quality level. Use a value between 40 and 80 for strong size reduction while keeping images recognizable. - **`compressImages(int quality, boolean scaleImageResolutionToVisibleSize)`**: Adds resolution scaling. When `true`, the library detects images that are rendered at a fraction of their native resolution and scales them down accordingly. This option offers the most aggressive size reduction but increases processing time slightly. [[t:(Apply multiple passes to fine-tune the size and quality balance. Start with a moderate setting like 70%, check the output file size, then decide whether a second pass at lower quality is warranted.)]] Running a 60% compression pass on an image-heavy PDF typically reduces file size by 50-70% depending on the source images. A document with primarily text content will see much smaller gains. Compare the before and after file sizes in the output directory to evaluate the result for your specific documents. For documents that need other processing alongside compression, `IronPDF` supports [extracting text](https://ironpdf.com/java/examples/extract-text-from-pdf/), [extracting images](https://ironpdf.com/java/examples/extract-image-from-pdf/), and [splitting PDFs](https://ironpdf.com/java/examples/split-pdfs/). ### What Does the Original PDF Look Like?  ### What Are the Results After Compression?  ## How Do I Choose the Right Compression Quality Setting? Choosing the correct quality level requires balancing file size against visual fidelity. The right setting depends on the document's purpose and the sensitivity of its embedded images. The table below gives practical guidelines for common use cases: *IronPDF Image Compression Quality Level Guide* | Quality Level | Approx. Size Reduction | Best For | | --- | --- | --- | | 80-100% | 10-30% | Print-quality documents, medical records, legal filings | | 60-79% | 40-60% | Internal reports, web download PDFs, email attachments | | 40-59% | 60-75% | Thumbnail previews, draft documents, archival copies | | Below 40% | 75%+ | Heavily degraded output; generally not recommended for distribution | Resolution scaling works best when the source PDF was assembled from high-resolution photographs or scanned pages but the document is intended only for screen viewing. In those cases, scaling resolution can reduce file size without a perceptible change in quality at normal zoom levels. For further context on PDF image encoding standards, refer to the [JPEG 2000 format documentation at the Library of Congress](https://www.loc.gov/preservation/digital/formats/fdd/fdd000143.shtml) and the [PDF image compression discussion on Stack Overflow](https://stackoverflow.com/questions/37019731/pdf-compression-techniques). [[n:(Avoid compressing PDFs that contain digital signatures. Modifying embedded images changes the document's binary content, which will invalidate existing signatures.)]] ## How Do I Reduce PDF File Size Further Beyond Image Compression? Image compression handles the largest contributor to file size in most PDFs, but additional techniques can reduce size further when combined. `IronPDF` supports several approaches that complement `compressImages()`: **Remove unneeded pages.** Deleting pages before compressing reduces both image data and page structure overhead. Use the [page deletion examples](https://ironpdf.com/java/examples/delete-specific-pages/) to remove blank or redundant pages first. **Strip annotations.** Annotation objects add binary data to the file. Removing them with the [annotation management API](https://ironpdf.com/java/examples/annotations/) before saving can reduce file size noticeably in documents with heavy markup. **Process documents in bulk.** For workflows that compress many PDFs, iterate over a list of file paths and apply `compressImages()` in a loop. `IronPDF` handles each document independently, so batch processing does not require special configuration; see the [pdf-compression example](https://ironpdf.com/java/examples/pdf-compression/) for a starting point. For a broader discussion of PDF optimization strategies, the [PDF file format specification at the Library of Congress](https://www.loc.gov/preservation/digital/formats/fdd/fdd000030.shtml) documents the structural elements that contribute to file size and how they can be reduced. ## What Are the Next Steps for Compressing PDFs in Java? `IronPDF`'s `compressImages()` method provides a practical way to reduce PDF file size in Java applications. A single method call with a quality integer covers most use cases, and the optional resolution scaling parameter handles image-heavy source files that need the most aggressive reduction. Start with a free trial to test compression on your own documents: - [Start your free trial](#trial-license): no credit card required - [View licensing options](#licensing): licenses start from `$liteLicense` Ready to see what else `IronPDF` can do? Check out the full Java PDF tutorial library here: [IronPDF Java How-To Guides](/java/how-to/java-create-pdf-tutorial/)

• ---

• Open in ChatGPT

  Ask ChatGPT about this page
• Open in Gemini

  Ask Gemini about this page
• Open in Grok

  Ask Grok about this page
• Open in Perplexity

  Ask Perplexity about this page

Share

• Share on Facebook
• Share on X (Twitter)
• Share on LinkedIn

• ---

• Email article

IronPDF enables Java developers to compress PDF files by reducing image quality and scaling resolution, helping reduce file sizes for easier sharing and storage.

import com.ironsoftware.ironpdf.*;
import java.nio.file.Paths;

// Load your PDF document
PdfDocument pdf = PdfDocument.fromFile(Paths.get("source.pdf"));

// Compress images to 60% quality
pdf.compressImages(60);

// Save the compressed PDF
pdf.saveAs(Paths.get("compressed.pdf"));

import com.ironsoftware.ironpdf.*;
import java.nio.file.Paths;

// Load your PDF document
PdfDocument pdf = PdfDocument.fromFile(Paths.get("source.pdf"));

// Compress images to 60% quality
pdf.compressImages(60);

// Save the compressed PDF
pdf.saveAs(Paths.get("compressed.pdf"));

PDF documents are widely used for sharing and storing information, but image-heavy files can reach tens of megabytes very quickly. Large file sizes complicate email delivery, slow down uploads, and inflate storage costs. IronPDF's Java compression API addresses this by letting you reduce embedded image quality and scale resolution in a few lines of code.

This article covers how to compress PDF files in Java using IronPDF. The examples show both simple quality-based compression and resolution scaling, so you can match the approach to your specific size and quality requirements. If you are also working with image-heavy PDFs or need to handle merged documents, compression is an essential step before distribution.

What Is the IronPDF Java PDF Library?

IronPDF is a Java PDF library that creates, reads, and manipulates PDF documents programmatically. The library handles HTML to PDF conversion, form filling, image embedding, and file compression without requiring a PDF viewer or external rendering engine. It supports various deployment environments including AWS Lambda, Azure Functions, and Google Cloud.

Compression in IronPDF works by resampling embedded images to a lower JPEG quality level and, optionally, reducing their resolution to match the display size in the PDF. Text, vector graphics, and document structure are not affected. This makes IronPDF a practical choice for large documents that need to be transferred quickly over email or stored in cloud-based systems.

The library also works well alongside other document operations: you can compress a PDF that already has watermarks, background layers, and bookmarks, and all those features are preserved after compression.

How Do I Set Up IronPDF in a Java Maven Project?

Before compressing PDFs, add IronPDF to your project's Maven configuration. For full setup instructions, see the Get Started Overview.

• To install IronPDF in a Maven project, add the IronPDF Maven repository and dependency to your pom.xml file.

• Add the dependency to the <dependencies> section:

      <dependency>
          <groupId>com.ironsoftware</groupId>
          <artifactId>ironpdf</artifactId>
          <version>your_version_here</version>
      </dependency>

  XML

• Save your pom.xml and run mvn install to download the IronPDF dependency.

Once the dependency resolves, you can import and use IronPDF classes in your project. The latest published version of the IronPDF Java artifact is available on Maven Central. For production deployment, configure your license key before running.

How Do I Compress a PDF File in Java?

IronPDF compresses PDF files by targeting the embedded images inside the document. The compressImages() method accepts a quality integer from 0 to 100, where lower values produce smaller files at the cost of image sharpness. An optional second parameter instructs the library to scale down image resolution based on the display size in the PDF page.

import com.ironsoftware.ironpdf.*;
import java.io.IOException;
import java.nio.file.Paths;

public class App {
    public static void main(String[] args) throws IOException {
        // Load the source PDF from disk
        String src = "C:\\Image based PDF.pdf";
        PdfDocument pdf = PdfDocument.fromFile(Paths.get(src));

        // First pass: compress images to 60% quality
        // Lower values produce smaller files with more visible quality loss
        pdf.compressImages(60);
        pdf.saveAs(Paths.get("assets/document_compressed.pdf"));

        // Second pass (optional): compress to 90% quality with resolution scaling
        // The second parameter scales image resolution down to match display size,
        // which can reduce file size further but may cause distortion in some PDFs
        pdf.compressImages(90, true);
        pdf.saveAs(Paths.get("C:\\Compressed.pdf"));
    }
}

import com.ironsoftware.ironpdf.*;
import java.io.IOException;
import java.nio.file.Paths;

public class App {
    public static void main(String[] args) throws IOException {
        // Load the source PDF from disk
        String src = "C:\\Image based PDF.pdf";
        PdfDocument pdf = PdfDocument.fromFile(Paths.get(src));

        // First pass: compress images to 60% quality
        // Lower values produce smaller files with more visible quality loss
        pdf.compressImages(60);
        pdf.saveAs(Paths.get("assets/document_compressed.pdf"));

        // Second pass (optional): compress to 90% quality with resolution scaling
        // The second parameter scales image resolution down to match display size,
        // which can reduce file size further but may cause distortion in some PDFs
        pdf.compressImages(90, true);
        pdf.saveAs(Paths.get("C:\\Compressed.pdf"));
    }
}

The code loads a PDF from disk and applies compression in two passes to illustrate different strategies. The first compressImages(60) call reduces image quality to 60% and saves the result. The second call uses 90% quality but enables resolution scaling, which adjusts each image's pixel dimensions to match its visible area on the page.

The compressImages() method has two signatures:

• compressImages(int quality): Resamples all embedded images to the given JPEG quality level. Use a value between 40 and 80 for strong size reduction while keeping images recognizable.
• compressImages(int quality, boolean scaleImageResolutionToVisibleSize): Adds resolution scaling. When true, the library detects images that are rendered at a fraction of their native resolution and scales them down accordingly. This option offers the most aggressive size reduction but increases processing time slightly.

Running a 60% compression pass on an image-heavy PDF typically reduces file size by 50-70% depending on the source images. A document with primarily text content will see much smaller gains. Compare the before and after file sizes in the output directory to evaluate the result for your specific documents.

For documents that need other processing alongside compression, IronPDF supports extracting text, extracting images, and splitting PDFs.

What Does the Original PDF Look Like?

What Are the Results After Compression?

How Do I Choose the Right Compression Quality Setting?

Choosing the correct quality level requires balancing file size against visual fidelity. The right setting depends on the document's purpose and the sensitivity of its embedded images.

The table below gives practical guidelines for common use cases:

IronPDF Image Compression Quality Level Guide

Resolution scaling works best when the source PDF was assembled from high-resolution photographs or scanned pages but the document is intended only for screen viewing. In those cases, scaling resolution can reduce file size without a perceptible change in quality at normal zoom levels. For further context on PDF image encoding standards, refer to the JPEG 2000 format documentation at the Library of Congress and the PDF image compression discussion on Stack Overflow.

How Do I Reduce PDF File Size Further Beyond Image Compression?

Image compression handles the largest contributor to file size in most PDFs, but additional techniques can reduce size further when combined. IronPDF supports several approaches that complement compressImages():

Remove unneeded pages. Deleting pages before compressing reduces both image data and page structure overhead. Use the page deletion examples to remove blank or redundant pages first.

Strip annotations. Annotation objects add binary data to the file. Removing them with the annotation management API before saving can reduce file size noticeably in documents with heavy markup.

Process documents in bulk. For workflows that compress many PDFs, iterate over a list of file paths and apply compressImages() in a loop. IronPDF handles each document independently, so batch processing does not require special configuration; see the pdf-compression example for a starting point.

For a broader discussion of PDF optimization strategies, the PDF file format specification at the Library of Congress documents the structural elements that contribute to file size and how they can be reduced.

What Are the Next Steps for Compressing PDFs in Java?

IronPDF's compressImages() method provides a practical way to reduce PDF file size in Java applications. A single method call with a quality integer covers most use cases, and the optional resolution scaling parameter handles image-heavy source files that need the most aggressive reduction.

Start with a free trial to test compression on your own documents:

• Start your free trial: no credit card required
• View licensing options: licenses start from $999

Ready to see what else IronPDF can do? Check out the full Java PDF tutorial library here: IronPDF Java How-To Guides

Curtis Chau

Chat with engineering team now

Technical Writer

Curtis Chau holds a Bachelor’s degree in Computer Science (Carleton University) and specializes in front-end development with expertise in Node.js, TypeScript, JavaScript, and React. Passionate about crafting intuitive and aesthetically pleasing user interfaces, Curtis enjoys working with modern frameworks and creating well-structured, visually appealing manuals.

...

Read More