Reduce your PDF's file size with an adjustable compression level — processed entirely in your browser, no server upload.
📤 Click or drag a PDF file here
Each page is rendered to an image at a chosen quality level, then reassembled into a new PDF — entirely within your browser, producing significant reduction for image-heavy or scanned PDFs.
Since pages are rendered as images, very high compression can slightly soften fine text edges. Use a higher quality setting to preserve sharper text at a larger file size.
Yes, though very large or many-page PDFs will take longer to process since each page is individually rendered and re-compressed in your browser.
This tool reduces a PDF's file size by re-rendering each page at an adjustable compression quality and reassembling the result into a new, smaller PDF — all processed locally in your browser without uploading your document anywhere.
Rather than manipulating the PDF's internal structure directly (which requires format-specific optimization tools), this compressor renders each page as an image using PDF.js, applies JPEG-style compression to that image at your chosen quality level, and rebuilds a new PDF from the compressed pages using pdf-lib. This approach is particularly effective for PDFs containing scanned pages, photos, or high-resolution images, where the bulk of the file size comes from image data rather than text.
All rendering and compression happens directly in your browser — your PDF is never uploaded to a server.
Behind the scenes, this tool uses PDF.js to render every page of your document onto an HTML canvas at a scale determined by the quality setting — low quality renders at a smaller scale (1.0x) while high quality renders larger (1.6x) to preserve more detail. That canvas is then exported as a JPEG at a matching compression ratio (as low as 0.35 quality for the smallest files, up to 0.85 for the highest), and pdf-lib embeds each resulting JPEG into a freshly built PDF, one image per page.
Because every page becomes an image, the compression ratio you see depends heavily on what's on the page. A scanned document or a PDF full of high-resolution photos will shrink dramatically, since that's exactly the kind of content JPEG compression is built for. A PDF made mostly of plain text, by contrast, may already be close to its minimum size in its original form — rendering it as an image can occasionally produce a larger file than the original if the original relied on efficient vector text rather than embedded images.
One side effect worth knowing about: because this method renders each page to an image rather than optimizing the PDF's internal text and font objects directly, the output PDF's text is no longer selectable or searchable — it becomes part of the page image, just like a scanned document. This is an important distinction from "true" PDF optimizers that shrink file size while keeping the underlying text layer intact.
Application portals, college submission systems, and government forms often enforce strict upload size limits, commonly somewhere between 1-10 MB. When a scanned assignment, certificate, or ID document comes out of a scanner app at tens of megabytes, running it through this compressor at a lower quality setting is usually enough to get it under a typical portal's limit without needing separate desktop software.
If the PDF is headed to an email attachment or a web form with a size cap, the "smaller file" setting is usually the right call since legibility on a screen tolerates more compression. If you intend to print the document or it contains detailed diagrams or photos that need to stay sharp, the "higher quality" setting keeps more visual detail at the cost of a larger file.
Because every single page is individually rendered to a canvas, converted to a JPEG, and re-embedded, the time this tool takes is roughly proportional to the number of pages rather than the original file size alone. A 100-page scanned report will take noticeably longer to process than a 2-page letter, even if the letter's file size happens to be larger due to an embedded high-resolution logo. The progress bar tracks page-by-page completion so you can see it's actively working rather than stalled.
The result card shows the original file size, the compressed file size, and a reduction percentage calculated as the drop between the two. This number can vary enormously between documents — a PDF that was already image-heavy and uncompressed might shrink by 80-90%, while a PDF that was previously optimized elsewhere, or that's mostly plain text rendered as an image, might show a much smaller reduction or occasionally even a slight increase at the highest quality setting.
Since the whole process runs locally and takes only moments for most documents, it's practical to compress the same file at two or three different quality settings and compare the resulting sizes before deciding which one to download, rather than guessing which level will hit a target file size on the first try.