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Quick answer
To compress a PDF to 300KB, open Compress PDF, add your file and start with Moderate. If the size shown is still over 300KB, run it again on Extreme. Three or four scanned pages usually fit under 300KB.
How to compress a PDF to 300KB in 3 steps
Add your PDF
Open Compress PDF and drop in your file. PDFs up to 200 MB work, including scans.
Choose Moderate
Moderate is the best starting point for a 300KB target. The tool shows the original and compressed sizes, so you can check the result straight away.
Check the size and download
If the new size is under 300KB, download it. If not, see the fixes below.
What fits in 300KB
Text barely adds to a PDF's size. Scanned pages and photos are what make it heavy. As a rough guide:
Swipe to compare →
| Your PDF | Level to try | Under 300KB? |
|---|---|---|
| Typed document | Light or Moderate | Almost always |
| 3–4 scanned pages | Moderate or Extreme | Usually |
| Scanned ID plus a utility bill | Moderate | Usually |
| Many photos or a long scan | Extreme, then trim or split | Sometimes |
If your PDF is still over 300KB
- Try the next level up, up to Extreme.
- Remove blank or unneeded pages with Delete PDF pages, then compress again.
- If it is a scan, re-scan at 150 DPI in grayscale. It makes a much smaller file to begin with.
- Still too big? Split the PDF into two files and upload each one if the form allows it.
Scan settings that land under 300KB
The easiest way to hit 300KB is to create a smaller file from the start. If you are scanning a document for a 300KB limit:
- Resolution: 200 DPI is plenty for reading and printing. 600 DPI makes files several times bigger for no visible gain.
- Color: color only where it matters.
- Pages: three or four pages per file.
- Phone scans: use the Notes app on iPhone (Scan Documents) or Google Drive on Android, which crop and flatten pages automatically.
How to check a PDF's size in KB
- iPhone: in the Files app, touch and hold the PDF and tap Get Info.
- Android: in Files by Google, tap the three dots next to the file and choose File info.
- Mac: select the file in Finder and press Command-I.
- Windows: right-click the file and choose Properties, or switch File Explorer to Details view.
Compress PDF also shows the original and compressed sizes on screen, so you can check before you download.
Where you'll run into a 300KB limit
- Proof of identity and address uploaded together.
- Rental and lease applications.
- Tax and payroll documents sent through client portals.
- Medical or benefits paperwork with a couple of scanned pages.
Frequently asked questions
How do I compress a PDF to 300KB for free?
Open Zappy Compress PDF, add your file, choose Moderate and click Compress PDF. The new size is shown before you download, so you can confirm it is under 300KB.
Can every PDF be compressed to 300KB?
Not always. Long scanned documents may not fit in 300KB even on Extreme. Remove pages you don't need or split the file into parts.
Will the text still be readable?
Yes. Compression shrinks images and scans, not text, so typed words stay sharp at every level.
Can I keep color scans under 300KB?
Usually, for three or four pages on Moderate. Photo-heavy pages may need Extreme.
Should I use Moderate or Extreme for 300KB?
Start with Moderate, which keeps scans clearer. Only move to Extreme if the size shown is still over 300KB.
Does it work on iPhone and Android?
Yes. Open Compress PDF in Safari or Chrome and choose the file from Files or your Downloads.
What happens to my file?
It is compressed on our server and deleted automatically afterwards. It is never shared.