Compress PDF

Lighter files. Same important details.

Lossless mode recompresses PDF streams. Image mode creates a smaller, flattened copy and removes selectable text, links and forms.

How to use Compress PDF

1. Open your document from your device.
2. Adjust the settings and preview the result.
3. Read text results on screen or download your file. Your original remains untouched.

Local by design

Your documents are processed on your device. No account, payment or document upload is required.

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Reduce size without overlooking what the recipient needs

Compression is useful when a PDF exceeds a portal limit, is awkward to email or takes too long to transfer. The right setting depends on whether the document contains native text, scans, photographs or a mixture. A small-looking page can contain a large image, and a long text report can already be efficiently stored.

Start by recording the original size and checking the actual delivery limit. Some systems limit each attachment, while others limit the combined submission. Keep the original separately. Decide whether searchable text, forms, links, accessibility structure or signature evidence must remain usable before choosing a compression mode.

Try the least destructive option first

1. Open the PDF and choose lossless compression for the first attempt.
2. Create the result and compare its byte size with the source.
3. If it still exceeds the requirement, consider image mode only when a flattened visual copy is acceptable.
4. Adjust the available quality and resolution settings conservatively.
5. Download, reopen and inspect the final file before sending it.

Lossless mode recompresses supported PDF streams without intentionally rasterizing every page. It may produce only a small reduction, no reduction or occasionally a larger rewritten file. That can happen when the source is already efficient. A successful operation message does not mean a guaranteed percentage saving; compare the actual output size.

Understand what image mode removes

Image mode renders the pages and creates a flattened image-based PDF. It can reduce some image-heavy files, but native text also becomes pixels. Searchable text, live links and interactive forms are removed from that copy. It is not simply the same document with a smaller container around unchanged features.

Use it for a reading copy when appearance is the main requirement. Avoid it when a recipient needs to search or complete the form. OCR can later add recognised text to page images, but that introduces recognition errors and does not restore the original semantics. An accessible source should not casually be replaced by a raster copy.

Inspect the smallest meaningful detail at normal reading size and enlarged. Check decimal separators, thin lines, chart legends and faint handwriting. A photograph may look acceptable while small labels become ambiguous. Raise quality or reconsider the workflow when important information is lost; meeting a size limit does not justify an unreadable submission.

A useful acceptance check

Count pages and compare orientation, page edges and the first and last sections. Reopen the downloaded result, not only the preview. If barcodes or QR codes matter, test them with the intended reader. If printing matters, print a representative proof, because screen readability and paper readability can differ.

Do not repeatedly compress an already degraded derivative. Return to the original when changing settings so that quality losses do not accumulate unnecessarily. If the file cannot meet the limit without unacceptable degradation, consider removing genuinely unnecessary pages, using an allowed split delivery or obtaining a better scan. Check the recipient’s rules before changing the document structure.

For a full explanation of image resolution, noise and colour trade-offs, read Why scanned PDFs are so large. Use the print checklist when the final copy will be printed. Compression succeeds when the smaller file still serves its intended purpose.

Frequently asked questions

Is lossless compression guaranteed to shrink every PDF?

No. Already compressed sources may change little or grow slightly when rewritten. Compare actual sizes.

Why can I no longer select text after image compression?

Image mode creates page images and removes the original text layer. Choose lossless mode when preserving text behaviour matters.

Does lower quality always mean a better result?

No. It can blur important details. Use the least reduction that meets the delivery requirement.

Can compression preserve a certificate signature?

Do not rely on rewriting a signed PDF to preserve its original validation. Keep the signed original and follow the required workflow.

Why is my scan still large?

High resolution, colour and image noise can dominate size. A better source capture or a different permitted delivery structure may help more than repeated compression.