Compress PDF

Pick a level, or a size to fit under

The four levels trade quality for bytes. Light keeps JPEG quality 85 and images up to 2400 pixels on the longest side, which is more than a laptop screen shows. Balanced, the default, uses quality 70 and 1600 pixels and is hard to tell from the original on screen. Strong (quality 50, 1200 pixels) suits email and web uploads. Extreme (quality 35, 600 pixels) is for hard upload limits where legibility matters more than looks. If a portal gives you a number instead, type it into Fit under a size: PaperKit then runs the ladder from Light downwards, eight rungs in all, and stops at the first file that fits.

• Light: quality 85, longest side 2400 px
• Balanced: quality 70, longest side 1600 px
• Strong: quality 50, longest side 1200 px
• Extreme: quality 35, longest side 600 px

What gets re-encoded and what is left alone

JPEG images and losslessly stored images in RGB, grey or indexed colour are decoded and re-encoded as JPEG. An image is replaced only when the new version is actually smaller, so a photo that was already heavily compressed is kept as it was. Images with a transparency mask keep their mask and are re-encoded at the chosen quality without being downsampled, because the mask has to stay the same size. Everything else stays untouched: CMYK images, JPEG 2000 images, fax and JBIG2 scans, one-bit stencil masks, sixteen-bit images, images with a custom decode array, and anything under 2 KB such as icons and bullets. Page thumbnails embedded by some scanners are dropped. The result card lists what was re-encoded and what was skipped, with a reason.

Why a text-only PDF barely changes

If a document has no images, the only saving available is structural: duplicate objects, uncompressed cross-reference tables and unused space are rewritten into object streams, which typically removes a few percent. Fonts are the next biggest item and cannot be shrunk without re-subsetting them, which no browser tool does safely. When you type a target below what the text and fonts alone occupy, PaperKit says so instead of pretending: the message tells you the floor so you can remove pages or split the file instead.

Scans and photographed documents

A scanner app that saves at 300 dpi produces pages 2500 pixels tall, several megabytes each, when 1200 pixels is plenty to read on a screen and 600 is still legible. Balanced halves such a file; Strong usually gets it to a quarter. Black-and-white fax-style scans stored as CCITT or JBIG2 are already tiny per page and are left alone. If a scan comes out blurry at Extreme, go back one level: the limit is the pixel cap, not the quality number.

Common upload limits

Job portals and government forms often cap attachments at 100 KB, 200 KB or 500 KB; many content systems stop at 1 or 2 MB. A page of ordinary text is 20 to 60 KB, so a short text-only CV fits 100 KB without any image work, while a scanned certificate at Extreme is roughly 40 to 80 KB per page. Use Fit under a size with the exact limit and check the preview, then the size shown on the result card.

• 100 KB: one or two scanned pages, or a text-only document
• 200 KB: a short scanned form or a text CV with a photo
• 500 KB: a multi-page scan at Strong or Extreme
• 1 MB and 2 MB: most reports and presentations at Balanced

Private, free, and honest about limits

The PDF never leaves your browser: no upload, no account, no watermark, and the original file stays unchanged on disk while paperkit-compressed.pdf downloads. The tool does not remove metadata, change page sizes or touch the text layer, so a searchable PDF stays searchable. Encrypted PDFs are not supported. If the output would be larger than the input, PaperKit keeps the original and tells you.