Compress PDF to a Target Size

Most people who want to compress a PDF are not trying to save disk space. They are staring at an upload form that says something like "maximum 500 KB" and a file that is three times bigger. This tool is built for that moment: you choose the limit, and it works toward a file that sits safely under it.

How the compressor works

Dokurapi opens your PDF inside the browser tab with PDF.js, draws each page as an image, and rebuilds the document as a JPEG-based PDF with pdf-lib. It starts at a sharp setting (render scale 1.2, JPEG quality 78%) and steps down through lower scales and qualities only as far as needed. It stops at the first result under the safe target, which is your chosen limit multiplied by 0.94. That 6% margin protects you from portals that count sizes slightly differently.

The default preset is 500 KB. You can switch to 100 KB, 200 KB or 1000 KB, or enter any custom KB value.

What changes in the output

Because every page becomes a picture, the compressed file behaves differently from the original:

• Text can no longer be selected, copied or searched.
• Clickable links and fillable form fields are gone.
• Digital signatures are removed, so do not use this on a document whose signature must stay verifiable.

For scanned certificates, ID cards, mark sheets and letters, this usually does not matter, since those are already images. For a typed report that a reviewer may want to search, check whether the form really requires a small file before you flatten it. Your original file is never modified; you always get a new download.

Choosing the right target

Always use the limit printed on the form you are filling in. Requirements differ between job portals, universities and government exam systems, and they change between intakes, so the receiving portal's current instruction is the final authority.

If the target is not met

When even the lowest setting cannot get under the limit, the tool still gives you the smallest version it produced and tells you plainly that the target was missed. At that point you have a few options: remove pages the form does not need, split a long document into separate uploads, or rescan at a lower resolution. If your source is a set of phone photos, build the PDF with photo to PDF first and then compress it here. Before uploading, use check PDF size to confirm the exact byte count against the limit.

Everything runs locally. There is no account, no daily cap set by the site, and your file content and file name are never sent anywhere.