How to Reduce PDF File Size Without Losing Quality
Reduce the size of large PDF files online for free. Tips and techniques for making PDFs smaller — for email, upload limits and storage.
Why Are Some PDFs So Large?
PDF file size depends on content type:
- Text-only PDFs — usually 100KB–1MB. Small and efficient.
- PDFs with images — size depends on image resolution. High-res photos can add MB per page.
- Scanned PDFs — often 2–5MB per page since each page is a full-resolution image.
- PDFs with embedded fonts — fonts can add 500KB–2MB each.
- PDFs with metadata and bookmarks — minor but adds up.
The most effective compression strategies target the biggest contributor to file size.
Method 1: Online PDF Compressor (Fastest)
The quickest way to reduce PDF size is using Breklo's Compress PDF tool:
1. Upload your PDF
2. Choose a compression level:
- Basic — removes unused objects, lossless, 10–30% reduction
- Medium — re-renders at 72% quality, 40–60% reduction
- High — maximum compression, 60–80% reduction
3. Download the compressed PDF
For most use cases, Medium gives the best balance of size and quality.
Method 2: Remove Unnecessary Pages
If your PDF has blank pages, cover pages you don't need to share, or appendices that aren't relevant, remove them first with Delete PDF Pages. Fewer pages = smaller file.
Method 3: Split Large PDFs
If you only need to share part of a large document, split it or extract the relevant pages instead of compressing the whole thing.
Method 4: Reduce Image Resolution Before Creating the PDF
If you control how the PDF is created (e.g. from Word or InDesign), reduce image resolution to 150 DPI for screen use or 300 DPI for print. This prevents large PDFs from being created in the first place.
What Compression Level Should I Use?
| Situation | Recommended level |
|---|---|
| Text-heavy report or contract | Basic (lossless) |
| Presentation with images | Medium |
| Scanned document | High |
| Sending by email (under 10MB limit) | Medium or High |
| Uploading to a portal with size limit | High |
Realistic Compression Results
- A 50MB scanned PDF → ~8–12MB on High compression
- A 10MB image-heavy presentation → ~3–5MB on Medium
- A 2MB text report → ~1.5MB on Basic (minor reduction)
Results vary by document type. Image-heavy and scanned documents compress the most.
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Frequently asked questions
What is the best way to reduce PDF file size for email?
Use Medium compression on Breklo's Compress PDF tool. It typically reduces file size by 40–60% while keeping the document readable. Most email limits are 10–25MB, and Medium compression easily gets most PDFs under that.
Does reducing PDF size affect print quality?
Basic compression is lossless — print quality is preserved exactly. Medium and High compression re-render pages as images which may show slight softening when printed at very large sizes, but is fine for standard A4 printing.
Why is my scanned PDF so large?
Scanned PDFs store each page as a high-resolution image. A single scanned A4 page at 300 DPI is 1–3MB. Use High compression mode to re-render at a lower resolution and dramatically reduce the file size.
Can I compress a PDF multiple times?
You can, but there are diminishing returns. After the first compression, subsequent compressions produce little additional reduction. For maximum compression, use High mode in one pass.
Is there a free way to reduce PDF size on Mac?
Yes. In Preview on Mac, go to File → Export as PDF, and in the Quartz Filter dropdown choose Reduce File Size. Results vary, but it is free and built in.
How do I reduce PDF size without losing quality?
Use Basic compression mode. It removes unused objects and optimises the PDF structure without re-rendering any content. Typical reduction is 10–30%.