How small will my PDF get?

It depends on what is inside. Scans and photo-heavy files typically shrink 60–90 %; text-only PDFs are already small and may lose only a few percent.

Will the text become blurry?

No. Text and vector drawings are not touched. Only embedded images are downsampled, and at the recommended level they remain sharp for reading and printing.

No. The images are re-encoded on your device; nothing leaves your computer.

Is there a file size limit?

Around 500 MB in a desktop browser; large scans take a while because every image is processed locally.

PDF Tools

Compress PDF

Name: Compress PDF
Author: Miikka

Reduce a scanned or image-heavy PDF by 50–90 % without making the text blurry. Three levels: light, recommended and extreme.

By Miikka · CalcBrew · Updated Sep 24, 2026

Runs in your browser — files never leave your device.

Drop PDF files here

or click to browse · paste from clipboard · up to 500 MB each

Select files

Options

Compression

About Compress PDF

Most oversized PDFs are scans stored at 300–600 dpi or exports with uncompressed images. Downsampling those images to 150 dpi and re-encoding them as JPEG removes most of the bulk while text and vector graphics stay exactly as they were.

Everything happens in your browser: JPEG and uncompressed images inside the PDF are decoded, resized and re-encoded, and the file structure is rewritten with object streams. Images with transparency masks and exotic encodings are left untouched, which is why a few files shrink less than others.

How to compress PDF

Drop PDF file onto the box above, click it to browse, or paste from the clipboard.
Adjust the options if you need to — the defaults suit most cases.
Press Convert. The work happens on your device, so speed depends on your computer or phone.
Download the result — individually or all at once.

About the format

PDF · Portable Document Format · .pdf

The fixed-layout document standard: looks the same on every device and printer, which is why forms, invoices, contracts and reports are shared as PDF.

A PDF can contain vector text, embedded fonts, images, form fields, annotations and digital signatures.
Scanned PDFs are just pictures of pages; they need OCR before the text can be searched or copied.
PDF is an open ISO standard (ISO 32000) since 2008.

Related conversions

Compress ImagePopularOn-deviceReduce image file size, optionally to a target in KB.Merge PDFPopularOn-deviceCombine several PDFs into one, in the order you choose.PDF to JPGPopularOn-deviceEvery PDF page as a JPG image.Split PDFPopularOn-deviceCut a PDF into separate pages or page ranges.Rotate PDFOn-deviceTurn pages the right way up and save the PDF.PDF Page RemoverOn-deviceRemove unwanted pages from a PDF.

Frequently asked questions

Cite this calculator

APACalcBrew. (2026). Compress PDF. https://calcbrew.com/compress-pdf

MLA“Compress PDF.” CalcBrew, 2026, calcbrew.com/compress-pdf.

Link to https://calcbrew.com/compress-pdf. Results are estimates; cite the underlying formula or data source for academic work.