PDF compression works differently from image compression. Most of the file size comes from embedded images, fonts, and metadata — our tool optimizes all three.
Upload PDF Documents
Select your PDF files — scanned documents, reports, presentations, or ebooks. Encrypted and password-protected PDFs are not supported.
Select Compression Level
Choose screen quality for email sharing (smallest), ebook quality for balanced results, or printer quality to preserve maximum detail. Each level adjusts embedded image DPI and font handling.
Download Compressed PDFs
Download your optimized PDF with text, links, bookmarks, and form fields fully preserved. The document remains searchable and printable at your chosen quality level.
Why Choose Our PDF Compressor
Image Downsampling
Embedded images often account for 90%+ of PDF size. Downsampling high-res photos from 300 DPI to 150 DPI halves pixel count while staying sharp on screen.
Font Subsetting
A full font file can be 500 KB+. Subsetting keeps only the glyphs actually used in the document, often reducing font data to under 30 KB without affecting rendering.
Metadata Removal
PDFs carry hidden data: edit history, thumbnail previews, XML metadata, and duplicate objects. Stripping these can recover 5-15% of file size with no visible change.
Web-Optimized Output
Linearized PDFs rearrange internal objects so the first page loads instantly in a browser, without waiting for the entire file to download.
Email-Ready Compression
Most email providers cap attachments at 25 MB. Use screen-quality compression to get documents under the limit while keeping text perfectly readable.
Scanned Document Support
Scanned PDFs are essentially large images. Compression can reduce a 20 MB scan to under 2 MB by downsampling to 150 DPI and applying JPEG compression to embedded images.
The compression physics
How PDF compression works at this target
PDFs are containers — the file size comes from three sources: embedded images (usually 70-95% of total), embedded fonts (5-10%), and vector page content (rest). Compressing to a smaller target attacks the images first: recompressing each embedded image with JPEG at lower quality, then downsampling from 300 DPI (print quality) to 150 DPI (screen quality) or 96 DPI (mobile quality). A scanned 100-page PDF at 20 MB can hit 2 MB via this route without touching page count or layout. Text-only PDFs are already near their floor and rarely compress by more than 15-20%.
Real portals mapped to size targets
Which target size to pick for PDF
Different portals cap PDF uploads at different sizes. Pick the target that matches where you’re uploading rather than shrinking blindly — over-compressing wastes visible quality, under-compressing gets rejected.
Quick answers about compression targets, upload limits, format behavior, and the best cases for compressing PDF files.
How do I compress PDF files online?
Choose a target size, upload your PDF file, and click Compress. iFormat shrinks it to your chosen size while keeping quality as high as possible — free, no watermark, and no account needed.
What sizes can I compress PDF to?
You can target 50KB, 100KB, 200KB, 500KB, 1MB, or 2MB, each with its own dedicated tool. Pick the size that matches the upload limit or email cap you need to meet.
How does PDF compression work?
PDF compression targets embedded images — the largest component of most PDFs. The compressor downsamples high-resolution images (often 300+ DPI) to screen-appropriate resolution and re-encodes them with more efficient compression. Text, fonts, and vector graphics remain crisp and selectable.
Will compressing reduce PDF quality?
Text stays sharp and selectable at any compression level — only embedded images are affected. For scanned documents (image-only PDFs), compression reduces the scan resolution. A 300 DPI scan compressed to 150 DPI is still readable on screen but may lose fine print detail when zoomed or printed.
Is the PDF compressor free?
Yes. Compressing PDF files is free with no watermark and no sign-up. Paid plans only raise file-size and batch limits.
Are my PDF files kept private?
Yes. Uploads use an encrypted HTTPS connection, compression runs on an isolated worker, and both your original and the compressed file are deleted automatically within a short window — nothing is stored, shared, or used for training.
Will compressing a PDF break fillable form fields?
No. Form fields, checkboxes, and digital signatures are preserved during compression. Only embedded images are re-encoded — the PDF structure and interactive elements remain intact.
Can I compress a password-protected PDF?
PDF'nin bir sahip şifresi varsa (düzenlemeyi/yazdırmayı kısıtlıyorsa) ancak görüntülemeye izin veriyorsa sıkıştırıcı bunu işleyebilir. PDF'nin açılması için bir parola (kullanıcı parolası) gerekiyorsa, önce parolayı kaldırmanız gerekir.
Related Guides for PDF Compressor
Read file-size, upload, and quality guidance related to compressing PDF files.
