Compress PDF

Shrink scanned and image-heavy PDFs right in your browser. Adjust image quality and resolution to hit an email or upload limit, then download — your file is not uploaded to our servers for routine operations.

Drag & drop a PDF
or click "Choose File"

Last tested June 2026. We verified this tool's core flow — selecting input, processing, preview, and download — in current Chrome, Safari, and Firefox on desktop and mobile, and checked how it handles unsupported or oversized files.

What this tool is for

Large PDFs are almost always large because of images: scanned pages, photographs, screenshots, exported design files, or product catalogs. This tool targets exactly that. It opens your PDF in the browser, re-renders every page, and re-encodes the page images at a quality and resolution you choose, then rebuilds a new PDF. The result is a much smaller file that still opens anywhere a normal PDF does.

It is the right tool when you need a document under an email attachment limit, below a job-portal or government-form upload cap, or simply light enough to share quickly. It is not the right tool for a small, text-only PDF that is already compact — see the honest limitations below.

How to compress a PDF

Drop in your PDF, then choose two settings. Image quality controls how much detail each page image keeps — lower means smaller. Resolution controls how many pixels each page is rendered at — "Screen" is smallest, "High" keeps text and lines sharper. Turn on Grayscale when color is not needed, such as scanned text documents, for an extra reduction. Click Compress PDF, watch the per-page progress, compare the before and after size, and download.

Example: a scanned contract that won't attach

A common case is a phone-scanned, multi-page contract that comes out at 12 MB because each page is a full-resolution photo, while the email or portal only allows 5 MB. Set quality to around 60–70%, resolution to Balanced, and enable Grayscale if it is black-and-white text. The pages stay clearly readable, but the file often drops to 1–3 MB — comfortably under the limit — in a few seconds, in your browser where supported.

Privacy

This compression runs in your browser where supported. The PDF is read with a local copy of the rendering library, each page is drawn to a canvas on your own machine, and the new PDF is assembled locally. Your document is not uploaded to this site or any third party, which matters for contracts, IDs, medical forms, and anything else you would not want to send through an online upload service.

How your file is processed

PDF Compress runs in your browser using the pdf.js library (loaded from a CDN) to re-render each page, then rebuilds a new PDF locally with the jsPDF library (also loaded from a CDN). The PDF is processed on your device and is not uploaded to a server.

Quality and honest limitations

This tool works by rasterizing pages — turning each page into an image. That is why it is so effective on scans and photos, and it is also its main limitation. Because pages become images, selectable text, hyperlinks, bookmarks, and form fields are not kept, and crisp vector text becomes a picture of text that can look slightly softer at low resolution. For a small text-only PDF that is already efficient, rasterizing can even make the file larger — the tool will tell you if that happens so you can keep your original. In short: excellent for scanned and image-heavy PDFs, not meant for lightweight text documents.

Common problems and fixes

The file got bigger. Your PDF is probably text-based and already compact; keep the original. Still too large. Lower the quality, drop to "Screen" resolution, and enable Grayscale. Text looks soft. Move resolution up to "High" and raise quality a little. A big PDF is slow or runs out of memory. Each page is rendered at full size, so very large documents are heavy on phones — try it on a desktop, or split the PDF first. Nothing happens. Confirm the file is a real PDF and that your connection allowed the one-time rendering library to load.

Frequently asked questions

What kind of PDFs does this compress best?

Scanned documents and image-heavy PDFs, which are usually the large ones. The tool re-renders each page as an image and re-encodes it at your chosen quality, so photo and scan content shrinks a lot. Pure text PDFs are already small and may not benefit.

Are my PDF files uploaded to a server?

No. The PDF is read, rendered, and rebuilt in your browser where supported using local libraries. The file is not uploaded to our servers for routine operations.

Why did my text PDF get larger or look softer?

This tool rasterizes pages, meaning sharp vector text becomes an image. For text-only PDFs that are already compact, that can increase size or soften text. Use it for scans and image-heavy PDFs; keep text PDFs as they are.

How do I make the file smaller?

Lower the image quality, choose a lower resolution, and turn on grayscale if color is not needed. Each of these reduces the data stored per page.

Is there a file size or page limit?

There is no fixed limit, but very large PDFs use more memory because each page is rendered to a canvas. On phones or older machines, very large documents may be slow.

Does compressing remove text selection and links?

Yes. Because pages become images, selectable text, links, and form fields are not preserved. Keep the original if you need those.

Last updated: June 2026