Compress a PDF without uploading it

About this tool

Compress PDF makes a PDF file take up less space. In most big PDFs, the weight comes from the pictures: scanned pages, photos in a brochure, snaps pasted into a report. This tool finds those pictures, makes them smaller and re-saves them as JPG. Text, fonts, drawings and links are left alone, so words stay crisp and you can still select and search them. It also tidies the file’s inner structure into a more compact form.

It suits anyone stuck with an attachment that is too large: a tenant sending scanned payslips to an agent, a student handing in a photo-heavy report, a tradie emailing a quote with site photos, or someone whose application portal says “maximum 5 MB”.

The documents people need to shrink are often private, and most compression websites upload them to do the work. Here, your own browser does it, so the PDF stays on your device. There is no account, no watermark and no limit on how many files you compress, one after another.

How to use Compress PDF

1. Tap “Choose a PDF” or drop one onto the box. A card shows its name, page count and size.
2. Under “How much to shrink”, pick Light, Recommended or Strong. Recommended is already selected.
3. Press “Compress PDF” and wait a moment while the photos are re-saved.
4. Check the summary and flick through the before-and-after pages to see how they look.
5. Press “Download PDF”. The file is saved with “-compressed” added to its name.

ExampleAfter compressing, the summary reads like “12.4 MB → 3.1 MB · 75% smaller · 18 of 20 photos re-saved”. Your own numbers depend entirely on what is inside the PDF.

Features

• Three levels: Light keeps photos up to 3000 pixels on the longest side at 82% JPG quality, Recommended uses 2000 pixels at 70%, and Strong uses 1300 pixels at 50%.
• Only photos change. Text, fonts, vector drawings and links are untouched, so text stays sharp, selectable and searchable.
• A photo is replaced only if the new version is at least 10% smaller. Otherwise the original picture is kept exactly as it was.
• Never hands you a bigger file: if the result isn’t smaller, nothing is offered and you are told why.
• Side-by-side before and after view of the same page, drawn from both the original and the compressed file. Use the arrows to move through pages, or tap a page to see it full size.
• Transparent parts of images are left alone, and pictures stored in unusual colour formats are kept as they were rather than risk damaging them.
• Password-protected and damaged PDFs get a clear message straight away.
• The work runs in a background worker, so the page stays responsive on long documents.

Tips and good to know

• It works best on scans and photo-heavy PDFs, such as phone scans, brochures and photo reports. A PDF exported from Word with only text barely shrinks, because text already takes very little space.
• Strong makes photos look softer when you zoom right in. That is usually fine for email or an upload limit, but use Light for anything you plan to print.
• Photos set up for professional printing (CMYK, the four-ink print colour system) become RGB, the screen colour system, when they are re-saved. Keep your original if it is going to a print shop.
• There is no “compress to exactly 1 MB” option. If Recommended isn’t small enough, try Strong.
• Fonts, pages and hidden document details (metadata) are not removed. To drop pages you don’t need, split the PDF first.
• You need a recent browser: Chrome, Edge, Firefox, or Safari 16.4 or later. Older browsers see a message instead.