Compress PDF (without turning it into soup)

If you searched "compress PDF", you probably have an email limit, a portal with opinions, or a document that grew to 38 MB for no clear reason. Here's how to shrink it without surprises — and what we do and don't solve.

Real-world scenarios

• Email or portal limit: You need to send a PDF under 5 MB (or 10 MB). Compress once, check readability, then send.
• Scanned docs and photos: Big images are the usual culprit. Reduce resolution gently; avoid crushing text readability.
• One big "kitchen sink" file: Multiple sections, embedded fonts, thumbnails. Compress to trim fat; split if it's still too big.

What we solve (and what we don't)

We solve: Shrinking PDF file size in the browser, no upload — by reducing image quality and stripping unnecessary data. You keep control on your device. We don't: Edit text or layout inside the PDF, OCR scanned pages into editable text, or guarantee a specific target size (results depend on the source).

Five common errors and how to avoid them

1. Compressing too aggressively: Sliders set to "maximum" can make text or diagrams unreadable. Compress once, then check the result before sending.
2. Assuming every PDF will shrink a lot: Text-only PDFs are already small. The biggest gains are with image-heavy or scanned files.
3. Forgetting metadata: Sensitive docs may contain names, software, timestamps. Remove metadata if the file will be shared.
4. Uploading to random sites: For confidential documents, prefer local-in-browser tools so the file never leaves your device.
5. One shot and send: Always open the compressed PDF and skim it. Fix rotation or re-compress with different settings if needed.

Privacy note

When compression runs locally in your browser, your PDF never leaves your device. That's the default for FilKlar's compress tool — no account, no storage on our side. For sensitive documents, prefer local compression over upload-based services. See our privacy and security pages for more.

FAQ

Will compressing reduce quality? It can reduce image quality and sometimes text sharpness if you push settings high. We recommend compressing once and checking the result before sending.

Is there a size limit? In practice, device memory and browser performance set the limit. Very large files (e.g. hundreds of MB) may need to be split first, then compress each part.

Do I need to upload my file? No. With the local compress tool, the file stays on your device. The browser reads it and writes the compressed PDF locally.

Can I compress scanned PDFs? Yes. Scanned PDFs are usually image-heavy, so compression often helps a lot. Reduce resolution gently to keep text readable.

The file is still too big after compressing — what now? Split the PDF into parts and send separately, or reduce image resolution a bit more if the content is mostly scans/photos.