Need to reduce a PDF file size for email, upload, or storage — without making it look blurry or unreadable? Here's how to compress a PDF for free, with full control over the quality vs file size trade-off.
Free, instant, three compression levels. Files never leave your browser.
Compress PDF Free →PDF file size is almost always driven by images. A PDF containing mostly text is typically tiny — just a few kilobytes per page. But as soon as you add photos, diagrams, scanned pages, or screenshots, the file size balloons quickly.
The most common culprits behind large PDFs are:
Compression works by re-encoding embedded images at a lower resolution and quality level, removing the excess data that isn't needed for typical viewing or printing.
TidyPDF's Compress PDF tool gives you three compression levels, so you control exactly how much quality you trade for file size savings.
Go to tidypdf.io/tools/compress-pdf on any device. No account required.
Drag and drop your PDF onto the upload area, or click to browse. Your file is loaded into your browser — never sent to any server.
Select Low for best quality, Medium for the recommended balance, or High for the smallest possible file size. See the guide below for which to choose.
The tool re-renders each page at the chosen quality level and rebuilds a fresh, smaller PDF — all in your browser.
Your compressed PDF downloads with a report showing the original size, new size, and percentage saved. Open it and check the quality looks good before sending.
10–30% size reduction. Virtually no visible quality difference. Best for documents where clarity is critical — contracts, medical records, print-ready files.
40–60% size reduction. Sharp and readable on screen. Minor softening of photos that's barely noticeable. Best for most use cases — email, sharing, uploading.
60–80% size reduction. Noticeable softening of images. Best when file size is the priority and photo quality is less important — quick shares, previews, drafts.
💡 Tip: If you're compressing for email, Medium compression is almost always the right choice. Most email size limits are 10-25MB, and Medium will get you well under that while keeping the document perfectly readable.
The reduction depends heavily on what's in your PDF:
After compression, TidyPDF shows you exactly how much was saved — the original size, the new size, and the percentage reduction.
This is the key question. The honest answer is: it depends on the compression level you choose.
At Low compression, the quality difference is nearly imperceptible — images are re-rendered at 90% quality and 1.5x scale, which produces files that look essentially identical to the original on screen and when printed.
At Medium compression, there's a slight softening of photographs and detailed images. Text remains perfectly sharp. For most documents — reports, invoices, forms, presentations — Medium compression produces output that looks completely professional and is indistinguishable from the original for most viewers.
At High compression, the quality reduction becomes noticeable, particularly in photographs. Text is still readable but images may look visibly softer. This is acceptable when you need the smallest possible file and aren't concerned about image quality.
💡 Important: Because TidyPDF re-renders pages as images, the output PDF won't have selectable text. This is a trade-off of browser-based compression. If you need to keep text selectable, server-based tools like Ghostscript preserve the text layer — but they require uploading your file.
| Tool | Free | No signup | Files stay on device | Quality control | No watermark |
|---|---|---|---|---|---|
| TidyPDF | ✓ | ✓ | ✓ | ✓ 3 levels | ✓ |
| SmallPDF | ✗ 2/day | ✗ | ✗ | ✗ | ✓ |
| iLovePDF | ✗ Limited | ✗ | ✗ | ✗ | ✓ |
| PDF24 | ✓ | ✓ | ✗ | ✓ | ✓ |
If your PDF has pages you don't need — blank pages, cover sheets, appendices — use the Split PDF tool to extract only the pages you need before compressing. Fewer pages means a smaller file.
If you're creating a PDF from images, compressing those images first (using a tool like TinyPNG for photos) will result in a smaller PDF from the start.
If you're creating the PDF from Word, PowerPoint or another application, look for export settings like "Optimise for web" or "Reduce file size" — these can significantly reduce the size before you even need to compress.
Free, instant, three compression levels. Files never leave your device.
🗜️ Compress PDF Free →