Tips for Optimizing PDF Download Size and Speed

Tips for Optimizing PDF Download Size and Speed

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February 15, 2023

PDFs are an essential part of many websites and are used to share information and documents with users. However, large PDF files can cause slow loading times and poor user experience. Learn how to reduce PDF file size and improve download speed with our easy tips. From compressing images to removing unnecessary elements, discover the best practices for optimizing your PDF.

Optimizing PDF

Table of Contents

How to Optimize a PDF file

1. Reduce the number of images in the document. If possible, use vector-based images instead of raster images, as they take up less space.

2. Compress images. Use tools like Adobe Acrobat or online services to compress images within the PDF.

3. Reduce the number of fonts used in the document. Stick to a few basic fonts and embed them in the document to reduce file size.

4. Remove any unnecessary elements from the document, such as comments or hidden layers.

5. Use a PDF optimization tool. Adobe Acrobat Pro has an option to optimize PDF files, which can reduce the file size without affecting the quality of the document.

6. Use PDF/A standard instead of PDF. PDF/A is a standardized format for long-term archiving of electronic documents. It allows the file to be more compressed and secure, also it can’t be modified.

7. Use PDF Lazy Loading. This technique loads only the visible part of the PDF and the rest of the content loads as the user scrolls. This allows for faster loading times for large PDFs.

Below we will look in detail at the most used and working methods.

#1 Optimizing PDF by Remove Unnecessary Embedded Files

Embedded files are any files that are included within a PDF document. These can include images, videos, audio files, and other multimedia. While these files can add value to a document, they can also take up a significant amount of space and slow down the loading time.

To remove unnecessary embedded files, you will first need to open the PDF document in a PDF editor. Adobe Acrobat Pro is a popular option, but there are also many free and open-source alternatives available.

  • In Adobe Acrobat Pro, you can find the embedded files by going to the “Tools” menu and selecting “Protect and Standardize.” From there, you can select “Manage Embedded Files” to view and remove any unnecessary files.
  • If you’re using a free or open-source PDF editor, you can typically find the embedded files by going to the “File” or “Edit” menu and selecting “Properties” or “Document Properties.” From there, you can view and remove any unnecessary files.

Recommendations for removing unnecessary embedded files:

1. It is important to be careful when removing embedded files, as they may be important to the document. For example, if you remove an embedded image that is used to illustrate a point in the text, the document may become difficult to understand.

Optimizing PDF
Optimizing PDF

2. Before removing any files, it’s a good idea to review the document and make sure that the embedded files are not necessary. If they are, they can be left in the document. But if they are not, you can safely remove them to reduce the file size and improve the loading speed.

3. Once you have reviewed and removed any unnecessary embedded files, you can save the document and test it to ensure that it is still suitable for its intended use.


PDFs are a popular format for sharing documents, but they can sometimes become quite large and slow to load. One of the main causes of this is the presence of unnecessary embedded files. By removing these files, you can significantly optimize the size and loading speed of your PDF file.

#2 Optimizing PDF by Reduce the Number of Images

Optimizing a PDF file for size and loading speed is important for ensuring that it can be easily shared and accessed by others. One effective way to do this is by reducing the number of images in the file.

Images are typically the largest contributor to the file size of a PDF, so reducing the number of images in the document can have a significant impact on file size.

Some tips for reducing the number of images in a PDF include:

  • Compressing images: By compressing the images in the PDF, you can reduce their file size without losing image quality. There are various image compression tools available online that can help you accomplish this.
  • Removing unnecessary images: If there are images in the PDF that are not essential to the content, consider removing them. This can include images that are used as decorations or background images that add little value to the content.
  • Using vector graphics: If the PDF contains diagrams, charts, or other graphics that can be represented as vectors, consider converting them to vector graphics. Vector graphics are resolution-independent and can be scaled up or down without losing quality.

#3 Optimizing PDF by Split Large PDFs

Splitting large PDF files can be a useful technique for optimizing the file size and download speed of your documents.

Here are some tips for how to split PDF files effectively:

  1. Use a PDF splitter tool: There are many free and paid PDF splitter tools available online that can help you easily split large PDF files into smaller, more manageable parts. Some popular options include Adobe Acrobat, PDFill PDF Editor, and PDF Split and Merge.
  2. Split by page range: One common way to split PDF files is by page range. This means that you can specify a range of pages that you want to extract from the original PDF and save as a separate file. This can be useful if you only need to share specific sections of a larger document.
  3. Split by file size: Another option is to split PDF files by file size. This can be useful if you want to ensure that the resulting files are small enough to easily share or upload to a website. For example, you could split a large PDF into multiple files, each with a maximum file size of 5MB.
  4. Split by bookmarks: If you have a large PDF that has bookmarks, you can split the file using the bookmarks. This is useful if the document has different sections, and you want to split it into separate files for each section.
  5. Compress the files: After splitting the PDFs, you can also compress the files to further reduce their size. Compression can be done using a variety of tools, such as Adobe Acrobat or online compressors.

By using these tips, you can effectively split large PDF files and optimize them for file size and download speed.

PDF Split And Merge

#4 Optimizing PDF by Compress Images

Compressing images is a crucial step in optimizing PDF file size and loading speed. Large, high-resolution images can greatly increase the file size of a PDF, making it take longer to load and impacting the user experience.

  1. Reduce Image Resolution: One of the easiest ways to compress images in a PDF is to reduce the resolution of the images. High-resolution images can greatly increase the file size, making it take longer to load. To optimize the file size, consider reducing the resolution of the images to 72 dpi or lower. This can be done using image editing software like Adobe Photoshop or GIMP.
  2. Compress Images Using Adobe Acrobat: Adobe Acrobat offers a built-in option for compressing images in a PDF. Simply open the PDF in Adobe Acrobat, go to the “File” menu, and select “Save As” and choose “Optimized PDF.” This will compress the images in the PDF, reducing the file size without sacrificing image quality.
  3. Use Online Compressors: There are also several online tools available that allow you to compress images in a PDF. These tools work by reducing the resolution and quality of the images, resulting in a smaller file size. Some popular online compressors are SmallPDF, Ilovepdf, and PDF Compressor.
  4. Use Lossless Compression: When compressing images, it’s important to use lossless compression to avoid losing image quality. Lossless compression techniques, such as PNG and GIF, will reduce the file size while preserving the original image quality.
  5. Optimize PDF for Web Viewing: To ensure that the PDF loads quickly on the web, enable the “Fast Web View” option in Adobe Acrobat. This option will optimize the PDF for web viewing, making it load faster for users.
  6. Use the Latest PDF Format: Using the latest version of PDF format like PDF 2.0 can also help with compressing images. PDF 2.0 has a new feature called JBIG2 which is a lossless compression algorithm specifically designed for monochrome images, this can help to compress black and white images.

#5 Optimizing PDF by Use Built-In Fonts

Embedding fonts in a PDF can greatly increase the file size. To reduce the file size, use fonts that are built into the PDF viewer, rather than embedded fonts. This will ensure that the PDF loads faster and takes up less space.

  • Use Built-In Fonts: Instead of embedding fonts in a PDF, use fonts that are built into the PDF viewer, such as Times New Roman, Arial, and Helvetica. This will ensure that the PDF loads faster and takes up less space. By using built-in fonts, the PDF will not need to include the font data, thus reducing the file size.
  • Use Standard Fonts: To ensure that the PDF can be viewed on different devices and platforms, use standard fonts that are widely available on most systems. This will ensure that the PDF will display correctly on a wide range of devices, without needing to embed the fonts.
  • Test the PDF: Before distributing the PDF, test it on different devices and platforms to ensure that the built-in fonts display correctly. This will help identify any issues and ensure that the PDF will display correctly for all users.
  • Use Web Fonts: An alternative to using built-in fonts is to use web fonts. Web fonts are hosted on a server and can be accessed by the browser, so the font data does not need to be embedded in the PDF. This can greatly reduce the file size and improve loading times.

#6 Optimizing PDF by using PDF/A

PDF is a widely used format for documents, but it can be difficult to optimize for search engines. One solution to this problem is to use PDF/A, a standardized format for archiving electronic documents.

Benefits of using PDF/A

  • Improved search engine visibility: PDF/A is designed to be search engine friendly, making it easier for search engines to crawl and index the content of your PDFs.
  • Better document preservation: PDF/A ensures that the formatting and content of your document will remain consistent, even if the software or hardware used to view the document changes.
  • Compliance with archival standards: Many organizations require that documents be saved in a standardized format for long-term preservation, and PDF/A is often the preferred

Best Practices for Optimizing PDFs using PDF/A

  • Use descriptive file names: Use descriptive and keyword-rich file names to make it easier for search engines to understand the content of your PDFs.
  • Use clear headings and structure: Use headings, subheadings, and other structures to make the content of your PDFs easy to navigate and understand.
  • Include meta data: Use the meta data fields in PDF/A to provide additional information about your document, such as the author, subject, and keywords.

Using PDF/A is a useful strategy for optimizing your PDFs for search engines. By following best practices such as using descriptive file names, clear headings and structure, and including meta data, you can improve the visibility and discoverability of your PDFs. By using PDF/A, you can also ensure the long-term preservation and accessibility of your documents.

If you want to learn more about PDF/A format, check out our other blog article:

What is PDF/A?

#7 Lazy loading

Lazy loading is a technique that can be used to optimize the loading speed of PDFs by only loading the content that is necessary for the user to see.

  • Determine the Load Priority: The first step in implementing lazy loading for PDFs is to determine the load priority of the content. This will help you determine which content should be loaded first, and which content can be deferred until later.
  • Load Content on Demand: Once you have determined the load priority, you can implement lazy loading by only loading the content that is necessary for the user to see. For example, if the PDF contains a large table of data, you can load the first few rows of the table, and then load the rest of the data on demand as the user scrolls through the table.
  • Use JavaScript to Load Content: To implement lazy loading, you can use JavaScript to dynamically load the content as the user interacts with the PDF. This will ensure that the content is only loaded when it is needed, and will help to improve the loading speed of the PDF.
  • Optimize PDF Structure: To further optimize the loading speed of the PDF, you can also optimize the structure of the PDF. This can include reducing the size of images, compressing the PDF, and optimizing the font size and style to reduce the file size.
  • Test the PDF: Before distributing the PDF, test it to ensure that lazy loading is working correctly and that the PDF is loading quickly and smoothly for users. This will help identify any issues and ensure that the PDF will display correctly for all users.

Lazy loading is an effective technique for optimizing PDF file size and improving loading speed. By determining the load priority, loading content on demand, using JavaScript to load content, optimizing the PDF structure, and testing the PDF, you can ensure that your PDFs load quickly and smoothly for your users. Remember that the best optimization technique will depend on the specific content and structure of the PDF, and some trial and error may be required to find the optimal solution.


In conclusion, reducing the number of images and fonts, removing unnecessary elements, and compressing the document can greatly reduce the file size of a PDF. Additionally, using a PDF optimization tool or PDF/A standard and implementing lazy loading can improve loading speed. However, it’s important to keep in mind that the final result of the PDF size and loading speed will depend on the content of the document, so it’s always a good idea to test different methods and compare the results.

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