Free PDF Compressor – Reduce PDF File Size Online

How to Compress a PDF Online

A large PDF can be difficult to email, upload to a website or store on a device with limited space. This often happens with scanned documents, image-heavy reports, presentations and files containing high-resolution graphics.

The free PDF Compressor from Tools Factory lets you choose how your PDF should be processed. You can repack the document while preserving selectable text or rasterize its pages into images with an adjustable quality setting.

1. Select your PDF file: Choose the PDF document you want to compress using the file input above.
2. Choose a compression method: Select either Repack PDF (Preserve Text) or Rasterize Pages (Remove Selectable Text and Links).
3. Enter image quality: Set a value between 0 and 1, such as 0.3, 0.4 or 0.7. This setting is particularly relevant when pages are converted into compressed images.
4. Start compression: Click the compression button and allow the tool to process your PDF.
5. Download and review: Save the resulting PDF and compare its file size, readability and page layout with the original.

What Is a PDF Compressor?

A PDF Compressor is a tool designed to reduce the storage size of a Portable Document Format (PDF) file. Depending on the compression method, it may reorganize document data, remove unnecessary overhead or convert pages into compressed images.

PDF files can contain selectable text, photographs, illustrations, scanned pages, embedded fonts, hyperlinks and other resources. These elements affect both file size and how much compression is possible.

Tools Factory provides two different approaches so you can choose between preserving document functionality and using image-based compression.

Understanding the Two PDF Compression Methods

The most important decision is choosing the right compression method. The two options behave differently and are suitable for different types of documents.

Method 1: Repack PDF (Preserve Text)

The Repack PDF option rebuilds the PDF structure while aiming to preserve the original text and page content.

This method is a sensible starting point when your document contains selectable text, links or other information you want to keep usable.

Repacking may reduce unnecessary structural overhead, but it does not guarantee a large reduction in file size. A PDF that is already efficiently compressed may become only slightly smaller or may not shrink at all.

Consider this method for:

• Text-based reports and office documents.
• Resumes, letters and application documents.
• PDF files containing selectable text.
• Documents where text readability matters more than maximum compression.
• Files you want to keep as close as possible to their original structure.

Important: Preserving text does not guarantee that every advanced PDF feature, annotation, form field or digital signature will remain unchanged. Review important documents after processing.

Method 2: Rasterize Pages (Remove Selectable Text and Links)

Rasterization converts each PDF page into a flat image. The images are then placed into a new PDF document.

This method changes the underlying document structure. Text that was previously selectable becomes part of an image, and hyperlinks no longer function as interactive PDF links.

Rasterization may produce a smaller file when the chosen image resolution and compression settings are suitable. However, the resulting file can also become larger, especially when a simple text-based PDF is converted into full-page images.

Consider this method for:

• Image-heavy PDF documents.
• Scanned pages and photographic documents.
• Files where a visual copy is sufficient.
• Documents where selectable text and active links are not required.
• Situations where you can accept some reduction in visual detail.

Important: Rasterization removes the original selectable text layer and interactive links. Do not choose this method when you need searchable text, accessibility features or editable document content.

Repack PDF vs Rasterize Pages: Which Should You Choose?

Both methods create a new PDF, but they make different trade-offs.

If you are unsure which method to use, try Repack PDF first. If the file remains too large and you do not need selectable text or links, test the rasterization method on a copy.

How to Choose the Right Image Quality

The image-quality input accepts a value from 0 to 1. This setting controls the quality level used when compressing rendered page images, particularly with the rasterization method.

Lower values generally use stronger lossy compression, which can reduce image data size but may introduce visible artifacts. Higher values generally preserve more image detail, although the output may be larger.

For example, you can enter 0.3, 0.4 or 0.7 in the image-quality field.

These are general guidelines rather than guaranteed results. The actual appearance and file size depend on the source PDF, image resolution and the compression library.

For text-heavy scanned documents, start with a moderate quality value and check the smallest text after compression. For photographs, compare image details before deciding whether the file is acceptable.

PDF Compression Example: Choosing Between 0.3 and 0.7

Imagine you have a scanned PDF containing 15 pages of printed notes. You want to make the file smaller before sharing it.

You could begin by selecting Rasterize Pages and entering an image-quality value of 0.7. After downloading the result, inspect the text and check the file size.

If the PDF is still larger than you need, repeat the process using the original file with a value of 0.4 or 0.3.

Lower quality settings may produce smaller image data, but they can also make small lettering, thin lines and diagrams less clear.

The best setting is the lowest quality value that still produces an acceptable result for your intended use. There is no single value that works equally well for every PDF.

Why Does PDF File Size Vary So Much?

Two PDFs containing the same number of pages can have very different file sizes.

A 50-page document made mostly of text may be smaller than a five-page document containing high-resolution photographs.

Common factors that affect PDF size include:

• Images: High-resolution photographs and scanned pages can require substantial storage.
• Image compression: The image format and compression settings influence file size.
• Embedded fonts: Some PDFs include font data to maintain consistent appearance.
• Vector graphics: Complex illustrations and diagrams can add document data.
• Document structure: Metadata, annotations, forms and other resources may contribute to file size.
• Existing optimization: A PDF that is already compressed efficiently may offer little room for further reduction.

Does Compressing a PDF Reduce Its Quality?

Not always. The effect depends on the compression method.

Repacking a PDF can sometimes reduce file size without visibly changing its pages. Rasterizing pages, however, converts text and graphics into pixels and may introduce image compression artifacts.

Small text, thin lines, detailed charts and signatures are particularly important to inspect after rasterization.

Compression does not improve the quality of an existing low-resolution scan. If the original document is blurry, the compressed version will not automatically become sharper.

Can You Compress Scanned PDF Documents?

Yes. Scanned PDFs often contain full-page images, which can make them relatively large.

Rasterization with image compression may help reduce the size of some scanned PDFs, depending on their existing resolution and compression.

However, scanning software may already have optimized the images. In that case, rasterizing the document again may produce little improvement or even increase the file size.

If your scanned PDF contains an OCR text layer, rasterization will remove that selectable text layer. Choose the repack method when preserving searchable text is important.

How to Compress a PDF for Email or Online Uploads

Email services, application portals and document management systems often limit the maximum size of uploaded files.

For example, a portal may require a PDF smaller than 2 MB. If your document is larger, you can test the available compression methods to see whether the resulting file meets that requirement.

1. Check the original PDF file size.
2. Try Repack PDF first if selectable text must be preserved.
3. Download the result and compare its size with the original.
4. If necessary, try Rasterize Pages using an appropriate image-quality value.
5. Open the compressed PDF and check every important page.
6. Confirm that the file meets the upload limit before submitting it.

Neither method guarantees a particular output size. The result depends on the document's contents and the compression settings.

What Happens to Text, Links and Digital Signatures?

PDF files can contain more than visible page content. Some include searchable text, clickable links, form fields, annotations and digital signatures.

The Repack PDF method aims to preserve the text content, but other advanced features may not always survive rebuilding the document.

The Rasterize Pages method creates image-based pages. Selectable text and active hyperlinks are removed, and the resulting document should not be treated as an accessible or editable equivalent of the original.

Creating a new compressed PDF can also invalidate existing digital signatures or omit signature information. Keep the original signed document when signature verification is important.

Tips for Getting Better PDF Compression Results

1. Choose the Method Based on Your Document

Use Repack PDF when you need to retain selectable text. Consider Rasterize Pages when a visual copy is sufficient and you can accept the loss of interactive features.

2. Start with Moderate Image Quality

A value around 0.6 can be a reasonable starting point for testing rasterized documents. Adjust the value after reviewing the actual result.

3. Check Small Text Carefully

Zoom in on small print, numbers, tables and diagrams. Compression artifacts may be difficult to notice when viewing an entire page at once.

4. Compare File Sizes

Check whether the new PDF is actually smaller than the original. Some files may increase in size after processing.

5. Keep the Original PDF

Always retain an uncompressed copy, especially when working with official documents, business records, contracts or important study materials.

Privacy and Browser-Based PDF Compression

Tools Factory provides browser-based utilities designed for everyday file tasks without requiring account registration.

This PDF Compressor is intended to process documents in your browser. Where processing is performed locally, the PDF contents do not need to be uploaded to a remote compression server.

Browser-based processing can reduce the need to transfer document contents to an external service, but you should still follow relevant privacy and document-handling requirements.

For more information, visit our About and Privacy page.

Common PDF Compression Problems and Solutions

The Compressed PDF Is Larger Than the Original

This can happen when the original PDF is already optimized or when rasterization creates large page images. Try the alternative compression method or adjust the image-quality setting.

The Text Looks Blurry

If you selected Rasterize Pages, the original text has been converted into image pixels. Increase the image-quality value and compare the result. Keep in mind that rendering resolution also affects sharpness.

I Cannot Select or Copy Text

The Rasterize Pages method removes the original selectable text layer. Use Repack PDF instead if text selection and searching are important.

Hyperlinks No Longer Work

Rasterization turns the page into a flat image, so interactive links are not retained. Choose a text-preserving workflow when active hyperlinks are needed.

The PDF Takes Too Long to Compress

Large documents, high-resolution scans and complex pages may require more processing time and memory. Try a smaller document to determine whether the issue is related to file size or complexity.

The PDF Cannot Be Processed

The file may be damaged, encrypted or incompatible with the processing library. Check whether it opens normally in a PDF reader and whether it has access restrictions.

Frequently Asked Questions

How can I compress a PDF online for free?

Select your PDF file, choose Repack PDF or Rasterize Pages, enter an image-quality value where applicable and start compression. Download the resulting PDF and check its size and readability.

What is the difference between Repack PDF and Rasterize Pages?

Repack PDF rebuilds the document while aiming to preserve selectable text. Rasterize Pages converts each page into an image and removes selectable text and interactive links.

What image-quality value should I use?

Start with a moderate value such as 0.6 and compare the output. Values such as 0.3 or 0.4 may apply stronger image compression, but they can reduce visual quality.

Does 0.3 mean the PDF will be reduced to 30% of its original size?

No. The value 0.3 represents an image-compression quality setting, not a target file-size percentage. The actual reduction depends on the PDF's content and the compression process.

Can I compress a PDF without losing selectable text?

Use the Repack PDF option, which is intended to preserve text content. The amount of size reduction may be limited, and you should verify the result after compression.

Will PDF compression remove hyperlinks?

The Rasterize Pages method removes interactive hyperlinks because it converts the pages into images. The Repack PDF method may retain links, depending on the implementation.

Can I compress a PDF to less than 1 MB?

It may be possible for some documents, but no particular output size is guaranteed. The result depends on the original file, page count, image content and selected settings.

Does rasterizing a PDF remove OCR text?

Yes. When the original pages are rendered into images without adding a new OCR layer, selectable OCR text is removed from the resulting document.

Will compressing a PDF change its page count?

Both compression methods are intended to preserve the document's pages, although you should verify that all pages were processed successfully.

Is higher image quality always better?

Higher values generally preserve more image detail but may produce larger files. The best value depends on whether your priority is readability, visual quality or file size.

Can I compress PDF files on a mobile phone?

Browser-based PDF compression can work on compatible mobile devices. Large PDFs and rasterization may require substantial memory and can perform better on a desktop computer.

Why is my PDF not getting smaller?

The original document may already be efficiently compressed, or the selected method may not reduce its largest components. Try another method and compare the results.

Where can I report a problem with the PDF Compressor?

If the compressor produces an unexpected result, report a problem with PDF Compressor. Include the selected method, image-quality value, approximate original file size and a description of the issue. Do not share confidential documents.