What a PDF compressor actually does
PDF file size is usually dominated by embedded images, high-resolution scans, and embedded fonts. A browser-based compressor like this one re-renders each page at a chosen resolution and re-encodes it as a JPEG inside a fresh PDF. That gives you a fast, predictable way to shrink a file for email attachments, government portal uploads, Applicant Tracking Systems that cap resume size, and general storage — at the cost of some fine detail. Because every step runs in your browser, your file is never uploaded to a third-party server and never retained after the tab closes.
When you actually need to compress a PDF
The most common reasons people end up on a page like this: an email provider refuses the attachment (Gmail caps at 25 MB, Outlook at 20 MB), a job portal or tax portal demands a resume or return under 100–500 KB, a contract management system wants every uploaded document under 2 MB, or the PDF was exported from a scanner at 300–600 DPI and is several times larger than it needs to be for on-screen reading. In all of these cases, a simple one-click compression is faster and more reliable than re-exporting from the original source.
How to use it
Upload your PDF, pick a compression level that matches how much quality loss you can tolerate, and optionally enter a target size in KB. Low is good for documents that still need to feel like the original — slight file-size reduction, text usually remains crisp. Medium is the best starting point for most users and typically cuts size by 40–70%. High aggressively re-encodes pages as images and can shrink scanned documents by 80% or more; text remains legible but fine lines and small fonts soften. Extreme pushes the tool to the smallest legible output possible — use it when a portal demands an unusually small target. If you hit a specific size cap, set the target KB field and the tool will iterate automatically until it either meets the target or reaches a safe readability floor.
Tips to get better results
- If the source PDF is a pure text document, compression gains will be small — the file is already close to minimal. Consider using Low to preserve selectable text.
- For scanned documents, compression gains are usually huge. Start with Medium or High and check the result on the first page for legibility before saving.
- If you still need more reduction, split the PDF first and compress individual sections separately, or remove pages you don’t need using our merge & split tool.
Benefits
- Smaller files that fit inside email size limits and portal upload caps.
- Faster uploads and easier archiving on mobile and spotty connections.
- Browser-only workflow — no signup, no watermark, and no server upload required.
- Target-size mode for hitting exact portal requirements (e.g. 100 KB, 200 KB, 500 KB).