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Compress PDF to 300 KB

To compress a PDF to 300 KB, each page is rendered at a reduced resolution and re-encoded as a JPEG until the whole file fits under 300 KB. The compressor on this page measures a real pass and adjusts, typically reaching the target in two passes, and reports the resolution it used. The document never leaves the browser.

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How to compress a PDF to 300 KB

  1. 01

    Add the PDF

    Drop the file onto the panel or choose it from disk. The file stays in the browser tab — it is not uploaded.

  2. 02

    Press compress

    The target size is already set. Resolution and image quality are selected automatically, so there is nothing to configure.

  3. 03

    Let it measure and adjust

    The compressor completes a pass, measures the result and runs again at a lower resolution if the file is still too large. Two passes is typical and four is the maximum.

  4. 04

    Check the reported size

    The result strip gives the final size, the settings used and whether the target was met. Download the file if it fits, or split a very long document and compress the parts.

Why 300 KB is the limit

A 300 KB limit appears on many registration systems that accept a multi-page supporting document rather than a single certificate.

Comfortable for fifteen pages at a readable resolution, and reachable for around fifty at the floor.

How much fits under 300 KB is decided by what is on the page, not by the page count alone. A photographic scan carries far more detail than black text on white and encodes to perhaps ten times the size at the same resolution, which is why this tool measures the document rather than predicting from its length. The first pass establishes how compressible the file actually is, and the resolution for the second pass follows from that measurement: output size scales with pixel count, and pixel count scales with the square of the resolution, so halving the resolution quarters the size.

What compressing to 300 KB costs

Reaching a fixed size target means rasterising: every page becomes a JPEG image, and the text layer, hyperlinks and form fields do not survive. The compressed file is a PDF of pictures of pages. It prints, it displays and it uploads, but it cannot be searched, selected or edited as text, and running it through optical character recognition later gives a worse result than the original would have. Keep the original and send the compressed copy only where a size limit demands it.

A document that is already small and text-only may not shrink at all, because a page of text stored as text is smaller than a picture of that same page. Compression of this kind pays off on scans and on documents carrying photographs, which is also what the size caps are usually aimed at.

Frequently asked questions

How do I compress a PDF to 300 KB?

Drop the file into the tool above and press compress. The target is already set to 300 KB, so resolution and image quality are chosen for you: the compressor makes a pass, measures the result and adjusts until the file fits. Nothing is uploaded — the document is rendered and rebuilt inside the browser tab, which is why no account or email address is asked for.

Why does a PDF need to be under 300 KB?

A 300 KB limit appears on many registration systems that accept a multi-page supporting document rather than a single certificate. A cap of this kind is enforced by the receiving form rather than by the PDF format itself, so the only way through it is to make the file smaller. Compressing locally avoids sending a document that may contain identity or financial details to a third-party server simply to reduce its size.

How many pages fit in 300 KB?

Comfortable for fifteen pages at a readable resolution, and reachable for around fifty at the floor. The honest answer depends on what is on the page: a photographic scan carries far more detail than black text on white and compresses to perhaps ten times the size at the same resolution. The tool measures the actual document rather than guessing from the page count.

Will the text still be selectable after compressing to 300 KB?

No. Reaching a fixed size target requires rendering each page to an image and re-encoding it as a JPEG, and that discards the text layer along with hyperlinks and form fields. The result is a PDF of pictures of pages. Keep the original if the text layer matters, and send the compressed copy only where a size limit demands it.

What happens if the PDF cannot reach 300 KB?

The compressor reports that the target was not met and returns the smallest file it managed, along with the resolution it stopped at. It will not keep degrading a document past the point of legibility to hit a number. A very long scan is the usual cause; splitting it into parts and compressing each is normally better than making every page unreadable.

Does compressing to 300 KB upload the file anywhere?

No. The document is read, rendered and rebuilt entirely inside this browser tab using the browser's own PDF renderer and canvas. No copy is transmitted, stored or logged, and the tool works with the network disconnected once the page has loaded. That matters for the identity documents and bank statements these size limits usually apply to.

Sources

Last reviewed: · See the methodology for how every tool on this site is built and verified.

Other target sizes

For a different figure, or to set resolution and quality by hand, use the PDF compressor.

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