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Compress PDF Online

Reduce PDF file size using the compression options available in PDFKaka, then review the result before downloading. The achievable reduction depends on the document's images, fonts, structure, and existing compression.

or drop the file here

Up to 50 MiB per PDF
View limits & supported files
Supported input
Select a PDF
Limits
Up to 50 MiB per PDF
Additional limits
Up to 100 pages
Processing
No file upload
File handling
Files remain in your browser
Browser processing No account required Direct download
Practical guidance

Reduce PDF size with a compression level that fits the document

Compression should balance file size against readability. Use the available mode that matches the document, then compare the result with the source before sharing or submitting it.

Start with the least destructive option

Use the recommended or structure-preserving mode first when selectable text, links, forms, or other PDF features matter.

Use stronger compression for image-heavy files

Scanned or photo-heavy PDFs may benefit from stronger image-focused compression, but the visible result should be checked carefully.

Measure the actual result

Review the original size, new size, and reduction shown by the tool. Compress PDF does not promise an exact target size.

About this tool

Make a smaller PDF without guessing what changed

Compress PDF should explain the trade-off between file size and document quality. Use the tool's real modes, keep the original, and inspect the downloaded copy before replacing or submitting anything.

Useful for

  • Prepare a PDF for an upload or email size limit.
  • Reduce scanned or image-heavy documents when practical.
  • Create a smaller sharing copy while keeping the original available.

Good to know

  • Exact size targets are not guaranteed unless a target-size mode actually exists.
  • Some PDFs are already compressed and may shrink only slightly.
  • Strong image compression can reduce readability of small text, signatures, diagrams, or photos.

How to Compress a PDF

Choose the PDF, select the supported compression mode, process it, and compare the resulting size and quality before download.

  1. Choose a readable PDF.
  2. Review the available compression options and select the mode appropriate for the document.
  3. Start compression and wait for processing to finish.
  4. Review the result metrics provided by the tool.
  5. Download the compressed copy and inspect important pages before use.
How to Compress a PDF

Related PDF tools

OCR PDF

Make supported scanned-document text searchable when the document also needs OCR.

Image Resizer

Reduce oversized source images before building an image-based PDF.

Merge PDF

Combine PDFs before or after compression when one document is required.

Flatten PDF

Fix supported interactive form-field values into page content when that workflow is needed.

Need another document task? Browse all working tools.

Browser processing questions

How much smaller will my PDF become?

There is no universal reduction percentage. The result depends on the document's images, fonts, structure, and how much compression is already present.

Does compression reduce PDF quality?

It can. Recommended compression preserves document structure where possible. Strong and Maximum compression rebuild every page as a JPEG image, which can reduce visual quality and remove selectable text, links, forms, annotations, accessibility data, and signatures.

Can PDFKaka compress a PDF to exactly 100 KB or 1 MB?

No exact output size is promised. Compress the file and check the downloaded result against your limit.

Can I compress scanned PDFs?

Yes. Scanned PDFs are supported, but image-heavy files may respond differently from text-based PDFs. Strong and Maximum compression rebuild pages as JPEG images.

Why did my PDF become only slightly smaller?

The source may already be compressed, may contain mostly efficient text/vector content, or may have document structures that cannot be reduced much without stronger changes.

Are my files uploaded to PDFKaka?

No. Selected file contents are processed locally in this browser during the normal workflow.

Practical PDF guides for complete tasks

Compress PDF guide How to compress a PDF and keep it readable Image-heavy and scanned PDFs usually offer the largest size reductions. Read guide → Compress PDF guide Why a PDF Will Not Compress Much and What You Can Do If Recommended compression produces little change, the document may already use compressed images or may consist mostly of compact text and vector content. Read guide → Compress PDF guide How to reduce the size of a scanned PDF Compress scanned or photo-heavy pages where image quality can be traded carefully for a smaller document. Read guide →
View all PDFKaka Guides →