Most email services limit attachments to 10-25MB. Compress your PDFs to fit within limits without splitting files.
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Form submissions
Government portals, job applications, and insurance forms often have strict file size limits. Compress to comply.
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Archiving documents
Reduce storage costs by compressing scanned documents, receipts, and contracts before archiving.
Two modes. Choose what fits.
Different PDFs need different approaches.
Smart
Optimize images inside PDF
Finds images embedded in your PDF and re-compresses them with Karui's next-gen engine.
Text, fonts, and layout remain untouched.
Best for: documents with photos, brochures, presentations
Render
Re-render pages as images
Converts each page into a compressed image for maximum size reduction.
The result is a clean, lightweight PDF.
Best for: scanned PDFs, maximum compression, archiving
Simple. Fast. Offline.
No uploads. No waiting. No file size limits.
1
Drop your PDF
Drag and drop one or multiple PDF files. Karui handles them all.
2
Choose Smart or Render
Smart preserves text. Render maximizes compression. Pick what you need.
3
Get your compressed PDF
Done in seconds. Email it, upload it, archive it.
Why Karui for PDF compression
No file uploads, ever
Online PDF compressors upload your documents to their servers. For contracts,
medical records, or business documents, that's a risk you don't need to take.
Karui processes everything locally.
No file size limits
Online tools often cap at 5-10MB per file, or limit you to a few files per day.
Karui has no size limits and no daily caps.
Images + PDFs in one app
Don't install separate tools. Karui compresses JPEG, PNG, HEIC, AVIF, and PDF — all in one app.
Convert HEIC to JPEG, compress images for web, and shrink PDFs for email. One workflow.
Mac and Windows
Works on both platforms. Same interface, same compression quality.
Use it on your work Mac and your home Windows PC.
Frequently asked questions
What is the difference between Smart and Render mode?
Smart mode finds and re-compresses images embedded inside your PDF while keeping text and layout intact.
Render mode converts each page into a compressed image for maximum size reduction.
Smart mode is best for documents with photos; Render mode for scanned PDFs or maximum compression.
Will compressed PDFs still be readable?
Yes. Smart mode preserves the original text and layout perfectly — only images are re-compressed.
Render mode converts pages to high-quality images that remain fully readable.
Can I compress scanned PDFs?
Yes. Scanned PDFs are essentially images, so they benefit greatly from compression.
Render mode is particularly effective, often reducing scanned PDF sizes by 70-90%.
Are my PDFs uploaded to a server?
No. Karui processes everything on your computer. Your files never leave your device.
Safe for confidential documents, contracts, medical records, and business files.
Can I batch compress multiple PDFs?
Yes. Drop multiple PDF files at once and Karui compresses them all.
Combined with image compression and HEIC conversion, it's one app for all your file optimization needs.