PDF Compressor
Shrink a PDF in your browser with adjustable resolution and JPEG quality, and see exactly how much you save.
Drag & drop a PDF here, or click to browse
No uploads. Your files stay on your device.
Preview of page 1 at the current settings.
How it works
Drop a PDF and it is compressed on the spot, inside your browser — the file is never uploaded to a server. Rasterise pages re-draws every page with PDF.js onto a canvas at the resolution you choose and re-encodes it as a JPEG, then rebuilds a fresh PDF with pdf-lib. That is where the big savings come from: scanned documents and image-heavy brochures routinely drop by 70–95%. The trade-off is that text on the page becomes part of the image, so it is no longer selectable or searchable.
Lossless restructure keeps every page object exactly as it is and only re-writes the file with compressed cross-reference and object streams. Text stays selectable and quality is untouched, but the saving is much smaller — and on a PDF that is already optimised the result can even be slightly bigger, which the tool will tell you. Start at Balanced, check the page-1 preview, and slide the resolution or JPEG quality down until the text still looks crisp enough. Grayscale shaves off a bit more on colour scans.
Frequently asked questions
How do I make a PDF smaller without uploading it?
Drop the PDF onto this page. It is read with FileReader, re-drawn page by page with PDF.js and rebuilt with pdf-lib entirely inside your browser tab, so the file never touches a server. Pick a compression level (Balanced is a good start), check the page-1 preview, then click Download compressed PDF. There is no upload queue, no file-size cap, no watermark and no sign-up, and the page keeps working offline once it has loaded — which matters when the PDF is a contract, a payslip or a medical scan.
Does compressing a PDF reduce its quality?
It depends on the method. Rasterise pages re-renders each page at the resolution you choose and stores it as a JPEG, so quality drops in proportion to the DPI and quality sliders — that is where savings of 70–95% on scans and image-heavy documents come from, and the live preview shows you exactly how it will look. It also flattens the page, so text becomes part of the image and is no longer selectable or searchable. Lossless restructure leaves every page object untouched and only rewrites the file with compressed object streams: quality and selectable text are preserved, but the saving is far smaller.
Why did my PDF get bigger instead of smaller?
Because it was already optimised. A PDF that is mostly vector text is extremely compact, so turning each page into a JPEG can produce a larger file than the original — the tool says so plainly instead of quietly handing back the same file. Fixes: lower the resolution and JPEG quality, tick Convert to grayscale, or switch to Lossless restructure, which never rasterises. If even lossless mode gains a few percent, your PDF is already about as small as it can get.