A free alternative to iLovePDF and SmallPDF for compressing PDFs

Compressing a PDF should be trivial: you have a 20 MB file that will not fit in an email and you just want it to weigh less. Yet almost every popular website adds some barrier —a size limit, a daily task cap, or the best mode locked behind a paid plan— and they share something more awkward: they ask you to upload the document to their server.

This guide compares how the best-known tools gate compression and presents an alternative that is free, unlimited and never uploads your file: it runs entirely in your browser.

How the most popular websites limit compression

It is not that they do not work; it is that the free version comes with conditions. As of this guide:

• SmallPDF lets you compress in a basic mode, but the strongest compression level is reserved for the paid account, and the free plan limits how many tasks you can run per day.
• iLovePDF compresses for free, but with size caps and a limit on how many files you can process at once without an account.
• PDFCandy allows free compression, but adds waits and limits between one task and the next.
• PDF24 is among the most generous —free and no sign-up— but it processes the file on its servers (deleting it after a while).

Let us clear up a myth: none of these tools stamps a watermark on the compressed PDF. The real friction is elsewhere: usage limits and, above all, having to upload your document. For a contract, a payslip or a medical record, uploading the file to a third party is not always acceptable.

The alternative: compress in the browser, free and without uploading

Colibrí's Compress PDF tackles exactly that. It is free, with no sign-up, no watermark and no usage or server-imposed size limit, because there is no server: the whole process happens inside your browser, using your own device's power. Your PDF is never uploaded anywhere.

In exchange for that privacy, it helps to understand how it compresses and when it shines.

How it works (and its honest limit)

The tool rasterizes each page: it redraws it as an image and re-embeds it as an optimized JPEG in a new PDF. That drastically shrinks scanned or photo-heavy documents, which tend to be the heaviest.

The trade-off, which we state plainly: turning a page into an image means the text is no longer selectable or searchable. So:

• If your PDF is a scan or full of images, it is the ideal case: big size savings.
• If your PDF is text only and already optimized, converting it to images would not make it lighter —it could even grow it—. In that case the tool detects this, warns you and returns the original untouched so it never makes things worse.

It is an honest approach: we would rather leave your file alone than hand you something worse than what you had. To keep the text selectable, save the original too.

Which level to choose

There are three levels, from the one that saves most to the one that keeps most quality:

• Maximum: the smallest possible size. Ideal for emailing or uploading to a form with a strict cap.
• Balanced: the best balance between size and sharpness. Recommended for most cases.
• Light: prioritizes quality; the saving is smaller. For documents you are going to print.

Step by step

1. Open Compress PDF and drag your file (or click to pick it). It opens in your browser; nothing is uploaded.
2. Choose the compression level for what you need.
3. Press Compress PDF and wait for the pages to be processed.
4. Check how much you saved and press Download.

If you also need to merge PDFs, split a PDF or rearrange pages with the PDF editor, the rest of the toolbox is right there, and they all work the same way: in your browser, nothing uploaded.