PDFSizeFit
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Large and scanned files

Compress a Large PDF

Shrink a scanned, image-heavy, or long PDF to a size you can upload or send. It's compressed in your browser, and you see the measured size before you download.

  • Files up to 100 MB
  • No upload or account
  • Starts at a 2 MB target

Your file never leaves this device — everything happens locally in your browser.

Compressing more than one PDF? Try batch compression.

Why it's big

What makes a PDF this large

A large PDF is almost always large for one of these reasons. Which one yours is decides how much it can shrink.

  • Scanned documents

    Shrinks the most

    Every page is a full-resolution photo of the paper. Twenty pages means twenty large images. See how to compress a scanned PDF.

  • Slides and reports with images baked in

    Shrinks well

    Exports that flatten each slide or page into a picture behave like scans. Their images get re-encoded the same way.

  • Long documents full of photos or diagrams

    Shrinks well

    Each embedded image is re-encoded at the highest quality that still fits your target.

  • Mostly text, but still big

    Limited

    Text is only repacked, so there may be little to gain. Repeated embedded fonts are a common cause, and exporting again from the original program is the better fix.

How it works

Compressing a large file, step by step

  1. Choose the file

    Up to 100 MB. It's read into your browser's memory, not sent anywhere.

  2. Keep 2 MB or set your own

    The target starts at 2 MB for a noticeably smaller file. If a portal gives you a number, type that instead.

  3. Give it a moment

    Big files take longer on your own device. After about 45 seconds the tool starts no new attempts, though one attempt on a very large file can take longer.

  4. Check it, then download

    Open the result and make sure small print is still readable before you send it anywhere.

Limits

Before you start

File size
Up to 100 MB per PDF.
Memory
The whole file is processed on your device. A phone or older computer may run out of memory on the biggest files.
Time
After about 45 seconds no new attempts start, and you get the best result so far. One attempt on a very large file can take longer.
Passwords
Password-protected PDFs aren't supported. Remove the password first.

FAQ

Frequently asked questions

See all frequently asked questions
Why is my PDF so large in the first place?

The most common cause is that every page is stored as a full-resolution image rather than text. That happens with scanned documents, and with slide decks or reports exported to PDF as flattened images. A 20-page scan at print resolution can easily reach tens of megabytes, since each page carries its own large image.

Will compressing a large scanned PDF make the text unreadable?

Usually not. The tool keeps the highest image quality that fits your target, and a scan that's large only because of its resolution normally still reads clearly. It won't go below a set minimum quality. If your target can't be reached above that, you get the smallest version it made, marked as a best effort. Open it and check it's readable before you send it.

Is there a limit to how large a PDF I can compress here?

Each file can be up to 100 MB. Because everything runs on your device instead of a server, large PDFs take longer and use more memory, and a phone or older computer may not have enough free memory for the biggest files.

Do I need to pick an exact target, or can I just make it smaller?

You can pick any target, including a loose one like 2 MB if you just want a noticeably smaller file. If a portal gives you an exact number, use that instead.