Email gateways reject attachments over 10 MB, court filing portals often cap at 25 MB, and university submission systems are stricter still. Most oversized PDFs are oversized for one reason: photographs and scans embedded at far higher resolution than anything a screen or office printer can reproduce.
Compress PDF re-encodes the images inside your document at a sensible target resolution and quality, strips redundant metadata and duplicate resources, and rewrites the file structure more efficiently. Text and vector graphics are left completely alone, so a compressed document is still crisp when you zoom in — it is the invisible 600 DPI photo detail that gets removed.
How to use Compress PDF
- 1Upload the PDF you want to shrink.
- 2Pick a compression level: Light keeps near-original fidelity, Recommended balances size and quality, and Strong targets the smallest possible file.
- 3Press Compress and watch the before/after size readout.
- 4If the result is too soft, step back a level and run it again on the original — never on an already-compressed output.
- 5Download the smaller file.
What actually gets compressed
Raster images are the target. They are downsampled toward a screen-appropriate resolution and re-encoded with a lower JPEG quality factor. Vector line art, embedded fonts and the text layer are preserved byte-for-byte, which is why a text-heavy report may barely shrink while a scanned brochure can drop by 90%.
Why compressing twice is a bad idea
JPEG compression is lossy and its artefacts compound. Compressing an already-compressed file produces visible blocking around text edges for very little extra saving. If you need a smaller result, discard the output and re-run the original at a stronger level.
Scans versus digital PDFs
A PDF exported from Word is mostly text and already efficient. A PDF made from phone photos is a stack of large JPEGs. If you are compressing a scan and also want searchable text, run OCR PDF before compressing so the recognised text layer survives at full fidelity.
Supported formats, limits and things to know
- Text-only PDFs typically shrink by 5–15%; image-heavy ones by 50–90%.
- Digitally signed PDFs will have their signature invalidated by any re-save, including compression.
- Encrypted files must be unlocked first.
- Compression is lossy for images — keep your original if you may need the full-resolution version later.
Compress PDF — frequently asked questions
How much smaller will my PDF get?
It depends entirely on the content. Scanned or photo-heavy documents commonly drop 50–90%. A text-only report may only lose 5–15% because there is little redundant data to remove.
Will compressing make my text blurry?
No. Text is stored as vector glyph instructions, not pixels, and is never re-encoded. Only embedded raster images are downsampled.
Can I compress a PDF below a specific size like 5 MB?
Try the Recommended level first and check the reported output size. If it is still above your target, re-run the original at Strong.
Does compression remove my document's metadata?
Redundant and duplicated internal metadata is removed. Core document properties such as title and author are preserved.
Is my document uploaded anywhere?
No. Compression runs locally in your browser, so even confidential filings stay on your machine.