Compress PDF

This free online PDF compressor reduces the file size of a PDF right in your browser — just drop a file in and the compressed version appears, with the size saved shown for you. It works by re-rendering each page at a chosen quality, which is especially effective for scanned and image-heavy PDFs. Nothing is uploaded, so your document stays completely private.

How to use

1. Drop in a PDF file.
2. It's compressed automatically at the Balanced level.
3. Switch to Strong for a smaller file or Light for higher quality.
4. Download the compressed PDF.

When compression helps — and when it doesn't

Scanned pages and PDFs full of photos shrink the most. Plain text PDFs are already efficient, so compressing them can actually increase the size and will turn the text into an image — in that case it's best to keep the original. The tool always shows the before and after size so you can decide.

How this compressor works, and what it costs

Each page is rendered to an image and re-encoded as JPEG, then reassembled into a new PDF. That is highly effective on scans and image-heavy documents, where the pictures dominate the file size and a modest quality reduction is invisible at normal viewing size.

The trade-off is real and worth stating plainly: text stops being text. After compression the words are pixels in a picture, which means they can no longer be selected, searched, or read aloud by a screen reader, and the file will not survive further editing well. For a scanned document that was already images, you lose nothing. For a PDF exported from a word processor, you lose quite a lot — and often the file gets bigger, because vector text and fonts compress far more efficiently than a photograph of them.

Try this first if the file is text

When a text-based PDF is too large, the cause is usually one or two oversized embedded images rather than the text. Before rasterising the whole document, it is worth extracting the pages you actually need with extract PDF pages, since a 40-page report trimmed to 6 pages is an 85% reduction with no quality loss at all. Removing pages beats degrading every one of them.

Check the result before you send it

The before-and-after sizes are shown for exactly this reason. If the output is larger, keep the original — that outcome is a signal that the document was already efficiently encoded. If the saving is worthwhile, open the compressed file and check the smallest text on the busiest page, which is where JPEG artefacts appear first. Everything runs in your browser, so the document is never uploaded regardless of which version you keep.