Question 1

Do you upload my PDF to a server?

Accepted Answer

No. Every page is rendered on your device with pdf.js, re-encoded as JPEG, and rebuilt into a new PDF with pdf-lib. Your file never leaves your browser.

Question 2

Which PDFs actually shrink?

Accepted Answer

Image-heavy PDFs — scans, photo reports, product brochures, presentations exported from Keynote/PowerPoint — usually shrink 40–70% at the Balanced setting. Text-only PDFs (contracts, articles, invoices) often stay the same size or slightly grow, because turning text into an image is not a size win.

Question 3

What is the difference between the three levels?

Accepted Answer

Low keeps pages near their original resolution and quality — expect small savings but crisp output. Balanced (recommended) renders pages at about 86 DPI with 70% JPEG quality — a good size-vs-quality trade-off. High renders at about 61 DPI with 50% JPEG quality — the smallest file, but text becomes noticeably softer.

Question 4

Is compression lossless?

Accepted Answer

No. This compressor is lossy — pages are rasterised to images and re-encoded as JPEG. This is exactly what browser-only tools do because they cannot inspect and re-compress internal PDF streams. If you need lossless compression, use a desktop tool such as Ghostscript or Adobe Acrobat.

Question 5

Are bookmarks, links, and form fields preserved?

Accepted Answer

No. Because every page is rebuilt from a raster image, interactive layers (form fields, annotations, hyperlinks, outlines) are dropped. Use Rotate PDF, Merge PDF, or Extract Pages if you need to keep those layers intact.

Question 6

What happens if compression makes my PDF larger?

Accepted Answer

You will see a friendly explanation — not an error. Text-only PDFs often become larger after image compression. We also offer a one-click download of your original file so you can keep it.

Question 7

What is the file size limit?

Accepted Answer

Up to 100 MB per PDF. Large files (hundreds of pages) take longer because every page is rasterised sequentially — expect a few seconds per page on a mid-range laptop.

Question 8

Does it work with password-protected PDFs?

Accepted Answer

No — encrypted PDFs cannot be read in the browser. Remove the password with a desktop tool first, then come back to compress.

Free PDF Compressor

Frequently Asked Questions

Merge PDF

Split PDF

Rotate PDF

Extract Pages