Compress PDF

Compress PDF Files Online

The Compress PDF tool helps reduce a document's file size for easier uploading, sending, and sharing. It provides two processing modes: optimizing the PDF structure or converting its pages to images when a different compression approach is needed for a complex document.

How to Compress a PDF

1. Select a PDF file from your device.
2. Choose the compression mode that suits the document.
3. Submit the file for processing.
4. Wait for the compression process to finish.
5. Download the new file and compare its size and visual quality with the original.

PDF Compression Modes

Optimize Structure

This mode reorganizes the PDF structure and compresses eligible elements while attempting to preserve searchable text, links, and document structure. It is the default and more suitable option for most documents.

Rasterize Pages

This mode converts every page into an image inside a new PDF. It can help with complex files or when structure optimization does not produce the desired result, but it may make text unselectable or unsearchable and can affect visual quality. The page rendering resolution and resulting image quality can be controlled with the Scale and Quality settings.

Scale and Quality Settings

The Scale and Quality fields appear only when Rasterize pages is selected:

1. Scale: accepts values from 1 to 4 in increments of 0.25. It controls the resolution used to render each page before it is placed as an image in the new PDF. A higher value may improve clarity, but it can require more processing time and may increase the resulting file size.
2. Quality: accepts values from 1% to 100%. It controls JPEG image compression in the resulting file. A lower value may reduce file size more, but it can cause a greater loss of detail, especially in scanned text and fine graphics.

Start with the default values shown in the interface, then compare the output with the original. There is no single setting that suits every file; a scanned document behaves differently from a PDF containing detailed photographs or illustrations.

Which Compression Mode Should I Use?

1. Start with Optimize structure for reports, contracts, invoices, and ordinary documents.
2. Try Rasterize pages if the first mode does not produce the required result or the PDF has a complex internal structure.
3. Review the downloaded file before deleting the original or sharing the new version.

Key Features of the Compress PDF Tool

1. A default mode for optimizing PDF structure.
2. An alternative mode that converts pages into images.
3. Adjustable Scale and Quality settings in rasterization mode.
4. Useful when a website or platform limits upload size.
5. Can make documents easier to send when the resulting file becomes smaller.
6. Works in the browser without requiring additional software.
7. Supports use on mobile devices and computers.

When Is PDF Compression Useful?

1. When a file exceeds an upload limit.
2. Before attaching a document to an email.
3. When sharing large reports, contracts, or invoices.
4. To reduce the storage space used by large documents.
5. To make a downloadable PDF faster to transfer when compression reduces its size.

Does Compression Always Reduce File Size?

No. The result depends on the PDF's structure, content, and any compression already applied. A file that is already efficiently compressed may show little improvement, and in some cases the processed file can become larger.

Compress PDF vs Linearize PDF for Fast Web Viewing

Use compression when the main goal is to try to reduce file size. Structure optimization reorganizes and recompresses eligible PDF data, while rasterization creates an image-based copy with adjustable page rendering resolution and JPEG quality. Rasterization may remove the ability to select or search text.

Linearize PDF reorganizes a document so a compatible web viewer can begin displaying its first pages before the complete file finishes downloading. Its purpose is progressive web viewing, not guaranteed file-size reduction.

Choose compression when an email service or platform imposes a size limit. Choose linearization when the PDF will be hosted online and you want it to begin displaying progressively while it downloads.

Frequently Asked Questions About PDF Compression

Which compression mode should I try first?

Start with Optimize structure because it preserves document features more effectively and is suitable for most files.

Does PDF compression affect document quality?

It depends on the selected mode and the file's content. Structure optimization usually has a limited visual effect, while rasterizing pages can produce a noticeable loss of detail at lower settings.

Will text remain searchable and selectable?

Text usually remains searchable after structure optimization. Rasterizing pages converts them to images, so the resulting text may no longer be selectable or searchable.

Is the original PDF changed?

No. The tool creates a processed copy and leaves the original file on your device unchanged.

What does Scale control in rasterization mode?

Scale controls the resolution used to render each page before it is added to the new PDF as an image. The interface accepts values from 1 to 4 in increments of 0.25. Increasing it may improve clarity, but it can increase processing time and output size.

What does the Quality setting control?

Quality controls JPEG image compression in the resulting file and accepts values from 1% to 100%. A lower value may create a smaller file with more visible detail loss, while a higher value retains more detail and may produce a larger file.

Why did the file size not decrease much?

The document may already be compressed, or it may contain elements that do not benefit much from structure optimization. The result depends on the content, selected mode, and settings.

Can the compressed PDF become larger?

Yes. This can happen when the source is already efficiently compressed or when rasterization uses a high Scale value and high Quality setting. Compare the size and clarity before using the result.