PDF Medic OnlineCompress PDF to 300 KB
Make a PDF smaller than 300 KB for an upload form — the box below is already set.
Files never leave your device
How to Compress PDF to 300 KB
- Press Choose a PDF, or drop the file on the box above. Its current size appears next to its name; the file itself stays on your device.
- If that size is already under 300 KB, you can stop here and upload the original. If not, keep Fit a size with 285 in Must be under (KB).
- Press Compress PDF.
- Check that the new size is under the form’s maximum and above any minimum it states, then press Download.
What fits in 300 KB
300 KB holds a few scanned pages, or one or two photo pages at a good level. Here is what our own test files gave; use it as a rough guide.
- A full A4 page of small print, scanned in colour: about 181 KB at Small. Three such pages: about 253 KB, at Smallest.
- A short scanned letter, about ten lines on A4: 69 KB at Best quality, hardly changed from its original 72 KB.
- A page with one detailed camera photo: about 194 KB at Balanced.
- Three pages with one detailed photo each: about 279 KB at Small, only just under.
- At Best quality the same photo page was about 480 KB, so photos almost always need Balanced or lower to fit here.
Landing inside a range
300 KB is often the top of a range, with a minimum such as 20 KB or 50 KB below it. Your file has to be under the top and over the bottom. Fit a size takes care of the top. The bottom is only a problem if the tool had to go much further than the form needs.
If the result is under the minimum, press Start over, choose the same file, and pick a level yourself instead of Fit a size. Try Best quality first, then Balanced, and keep the first result that sits inside the range. Best quality usually gives the biggest file and Smallest the smallest, with Balanced and Small in between.
If even your original is below the minimum, this tool cannot help, because it never makes a file bigger.
Just a little over 300 KB?
A file of, say, 320 KB doesn’t need heavy compression. Fit a size tries Best quality first. That level keeps up to 2400 pixels on a picture’s long side at a high JPEG quality, so the change to most scans is small. Only if that is still too big does the tool move on to Balanced.
Small pictures under about 20 KB, such as logos, are never touched. Neither are text and drawings. So a file that is over the limit because of its text and fonts, not its pictures, may not get under at all; then removing pages with Split PDF is the way. The main Compress PDF page explains which pictures are left alone and why.
Why 285
Here 1 KB is 1,024 bytes, so 285 in the box is 291,840 bytes. That is under 300,000 bytes, which is 300 KB on a site that counts 1 KB as 1,000 bytes. Typing 300 would allow up to 307,200 bytes and could be refused there.
Everything happens in your browser: your file is never uploaded to any server. You can check: once your file is open, turn on airplane mode — the tool still works.
Questions
How many pages can I fit in 300 KB?
In our tests, three full pages of small print scanned in colour fitted at Smallest, and one such page fitted at Small. Lighter pages, like letters with a few lines, fit in larger numbers. Typed pages with no scans take very little room.
My form says between 50 KB and 300 KB. Which number do I type?
Keep 285, the top of the range with a small margin. After compressing, check the new size is above 50 KB. If it is not, start over and pick Best quality or Balanced instead.
My PDF is 320 KB. Will compressing to 300 KB spoil it?
Usually not. The tool starts with Best quality, the gentlest level, and stops there if the file fits. Text is never changed.
Why is my result far below 285 KB?
The level above it came out too big, and there is no setting in between. The four levels are fixed steps, so the first one that fits can be much smaller than your number.
Is my file uploaded?
No. Compress PDF to 300 KB runs in your browser on your own device. The file is never sent to our server or anyone else. Once your file is open you can even turn on airplane mode.
Is it free?
Yes. No sign-up, no limits on how many files, and no watermark is added to your file.
Does it work on a phone?
Yes, in any modern browser on iPhone, Android, Mac, Windows or Linux. Very large files work best on a computer, because a phone browser has less memory.