Open DockFlip Compress PDF, add your PDF, pick Less, Recommended or Extreme, and download the smaller file. In our tests, a 9.29 MB scanned PDF dropped to 840 KB, and a 3.41 MB report with photos dropped to 203 KB. The text in your PDF stays selectable, because only the images inside are compressed. It is free, with no signup or watermark, and your file never leaves your device.
Why PDFs get so big
A PDF is a container. It can hold text, fonts, vector drawings and images, and the images are almost always the heavy part. A page of plain text is a few kilobytes. A page that is a photo of a document, such as a phone scan, can be 1 to 3 MB by itself.
That is why a 10 page scan can be 15 MB while a 40 page report exported from Word is only 300 KB. When you compress a PDF, nearly all of the saving comes from making those images smaller.
Which PDFs shrink a lot, and which do not
| Type of PDF | What is inside | How much it shrinks |
|---|---|---|
| Scanned document or phone scan | One large image per page | A lot, often 80% or more |
| Report or brochure with photos | Text plus large images | A lot, depending on the photos |
| Slides exported with pictures | Images and some text | Moderate to a lot |
| Text only, exported from Word or Docs | Text and fonts | Little or nothing |
If your file is mostly text and is already small, there is not much to remove. If you have the original Word or Docs file, see the export tip below.
How to compress a PDF in your browser
This works the same on Windows, Mac, iPhone, Android and Chromebook. You do not need to install anything.
- Open the tool. Go to Compress PDF on DockFlip.
- Choose your PDF. Tap Choose PDFs or drag the file onto the page. You can add several files at once.
- Pick a level. Less keeps images sharp, Recommended balances size and quality, and Extreme gives the smallest file. You can change the level after adding the file, and it compresses again.
- Check the result and download. The list shows the old and new size before you download. The file is named like
report-compressed-DockFlip.pdf, so your original stays untouched.
If the new file is not smaller, DockFlip says Already optimized and gives you your original back, so you never download a bigger file by mistake.
What each level does: our test results
We built three sample PDFs and ran each one through all three levels in DockFlip Compress PDF. The files are test samples, not your documents, and real files vary, so treat the numbers as a guide.
| Sample file | Original | Less | Recommended | Extreme |
|---|---|---|---|---|
| 6 page scanned document (A4, 300 DPI) | 9.29 MB | 4.29 MB (54% saved) | 2.07 MB (78%) | 840 KB (91%) |
| 4 page report with text and photos | 3.41 MB | 1.49 MB (56%) | 514 KB (85%) | 203 KB (94%) |
| 6 page text-only PDF | 4.9 KB | 3.4 KB | 3.4 KB | 3.4 KB |
Three things stand out. Images carry the saving, so the scan and the photo report shrank by more than half even at Less. Extreme gave the smallest files, and on the scanned page the text was still readable, only a little softer. And the text-only file barely changed, because there were no images to compress.
How to compress a PDF to 100 KB, 200 KB, 500 KB, 1 MB or 2 MB
Job portals, exam forms, visa sites and college systems often set a size limit such as 100 KB, 200 KB, 500 KB, 1 MB or 2 MB. Use the table as a starting point, then check the size in the result list.
| Limit | Start with | If it is still too big |
|---|---|---|
| Under 2 MB | Less or Recommended | Choose Extreme |
| Under 1 MB | Recommended, then Extreme | Split the PDF or remove pages |
| Under 500 KB | Extreme | Split the PDF into two parts |
| Under 200 KB | Extreme, best for 1 to 4 pages | Compress each part separately |
| Under 100 KB | Extreme, realistic for 1 to 2 pages | Keep only the pages you need, or split |
| Under 50 KB | Extreme, only for a single simple page | Remove images you do not need, or split |
The page count matters more than anything else. As a rough budget, plan for 30 to 50 KB per page at Extreme. A 2 page document can reach 100 KB, a 3 to 4 page one can reach 200 KB, but a 20 page scan usually cannot. In our test, the 4 page photo report landed at 203 KB, just above the 200 KB line, so pages with big photos can need a little extra work. We did not test the 100 KB and 50 KB targets, so treat those rows as a guide. A 50 KB limit is only realistic for one simple page, such as an ID proof or a signed form.
A PDF that is mostly text, such as a resume or a letter, is often already under 100 KB. If it is bigger, it usually has an image in it, such as a logo, a photo or a stamp, and that is what to compress.
How to compress a PDF without losing quality
"Without losing quality" depends on what is in the PDF. Here is what you can expect.
- Text stays sharp. Real text, fonts and vector lines are not touched, so they stay crisp at any zoom.
- Choose Less for the best image quality. In our test it still saved 54% on the scan and 56% on the photo report.
- Recommended is the usual choice. It saved 78% and 85% in our test, and for normal reading the difference is hard to see.
- Extreme trades some sharpness for size. Use it when a limit forces you, and zoom in on the result before you send it.
Compression of images is lossy, so no tool can shrink a photo-heavy PDF a lot and keep every pixel. What you can do is pick the lightest level that gets you under the limit.
How to compress a PDF on iPhone, Android, Windows and Mac
DockFlip runs in the browser, so the steps are the same on every device. You do not need an app.
- iPhone and iPad: open DockFlip in Safari, tap Choose PDFs and pick the file from Files or iCloud. Download the result and it saves to Files.
- Android: open DockFlip in Chrome, tap Choose PDFs and pick the file from your phone or Google Drive. The compressed file goes to Downloads.
- Windows: open DockFlip in Chrome or Edge and drag the PDF onto the page.
- Mac: open DockFlip in Safari or Chrome and drag the PDF onto the page. Preview can also reduce size, but it often lowers the quality strongly.
What happens to the text, fonts and links
DockFlip does not turn your pages into pictures. It looks for the images inside the PDF and saves each one again at a smaller size. Everything else is left alone.
- Real text stays real. You can still select, copy and search it.
- Links and layout stay. Page size, fonts and hyperlinks are not changed.
- Images get lighter. This is where the size comes from. The images are saved with lossy compression, so very fine detail can soften at Extreme.
- Scanned text stays an image. A scan is a photo of a page, so its text was never selectable. Compressing does not change that. To make a scan searchable you would need OCR, which is a different tool.
If the PDF is still too big
- Choose Extreme if you have not already.
- Remove pages you do not need. Use Split PDF to extract only the pages you need into a new file.
- Split into parts. Two 600 KB files are easier to send than one 1.2 MB file when a portal has a strict limit.
- Reduce the photos first. If you build the PDF from photos, resize and compress the images, then combine them with JPG to PDF. The guide on how to reduce image size shows the settings.
- Merge afterwards if needed. You can join the small parts again with Merge PDF, though the result will be larger than the parts.
Word export, Mac Preview, Adobe Acrobat and email limits
If you still have the Word or Docs file
Export again instead of compressing. In Word, choose Save As, select PDF, and look for the Minimum size (publishing online) option. It usually produces a smaller file than the standard export. Smaller images in the document also help.
In Adobe Acrobat
Acrobat Pro can reduce a PDF with File, Save as Other, Reduced Size PDF, or with the Optimize PDF tool for more control. It needs a paid plan. If you only need to shrink a file now and then, a free browser tool is quicker.
On a Mac
Preview can open a PDF and export it with a Reduce File Size filter from the Quartz Filter list. It can shrink files, but it often lowers the quality strongly, so check the result before you send it.
Email limits
Gmail allows attachments up to 25 MB and Outlook.com up to 20 MB. Many employers, schools and government sites set smaller limits, often 1 to 5 MB. Check the limit first, then pick the level that gets under it.
Is it safe to compress a PDF online?
PDFs often hold private things: contracts, ID scans, bank statements, medical forms. Many online tools upload the file to a server. DockFlip does the compression inside your browser, so the PDF is not sent to us. The first time you use the tool, your browser downloads the PDF library it needs from a public CDN, but your file is not part of that. A tool that uploads usually shows an upload bar and needs a good connection, while a local one starts the moment you pick the file.
Frequently asked questions
How do I compress a PDF to 50 KB?
Use Extreme in DockFlip Compress PDF. A single simple page, such as a signed form, can often get that small. Longer or photo-heavy files will not, so keep only the page you need with Split PDF first.
How do I make a PDF smaller?
Open DockFlip Compress PDF, add the file and pick a level. The images inside the PDF are saved at a smaller size, which is where most of the weight is. Text-only PDFs are already small. If it is still too big, split it or remove pages.
How do I compress a PDF in Adobe Acrobat?
In Acrobat Pro, choose File, Save as Other, Reduced Size PDF, or use Optimize PDF. It needs a paid plan. A free option is DockFlip Compress PDF, which runs in your browser and keeps text selectable.
How do I compress a PDF to 100 KB?
Open DockFlip Compress PDF, add the file and choose Extreme. A 1 to 2 page PDF can usually reach about 100 KB. For longer files, keep only the pages you need with Split PDF, or compress each part separately. A rough budget is 30 to 50 KB per page at Extreme.
How do I compress a PDF to 2 MB or less?
Start with Less or Recommended. In our test, Recommended brought a 9.29 MB scan to 2.07 MB, and Extreme brought it to 840 KB. If your file is still over 2 MB, choose Extreme.
How do I reduce PDF size on iPhone or Android?
Open DockFlip Compress PDF in your phone browser, tap Choose PDFs, pick the file and download the smaller version. There is no app to install, and the file stays on your phone.
What is the best free PDF compressor?
Look for a tool that is free without a watermark, lets you choose how strong the compression is, keeps text selectable, and does not upload your file. DockFlip Compress PDF does all four, with three levels: Less, Recommended and Extreme.
How do I compress a PDF to under 1 MB?
Open DockFlip Compress PDF, add your file and choose Extreme. In our test, a 9.29 MB scanned PDF with 6 pages came down to 840 KB. If your file is still over 1 MB, split it into two parts with Split PDF, or remove pages you do not need.
How do I compress a PDF to 200 KB or 500 KB?
Use Extreme first. It got a 4 page report with photos from 3.41 MB to 203 KB, and a 6 page scan from 9.29 MB to 840 KB. Long PDFs struggle to reach 200 KB, so split them or compress each part separately. A rough budget is 30 to 50 KB per page.
Will compressing a PDF reduce quality?
The images inside the PDF are saved again at a lower quality, so they can look a little softer, especially at Extreme. The text, if your PDF has real text, is not touched and stays sharp. Choose Less or Recommended to keep images sharper.
Can I compress a PDF and keep the text selectable?
Yes. DockFlip only compresses the images inside the PDF. Real text, fonts and links stay as they were, so you can still select, copy and search the text. Text that is part of a scanned page image was never selectable and stays an image.
Why is my PDF still big after compressing?
Large PDFs often contain a lot of pages or very detailed images. Try Extreme, split the file, or remove extra pages. A PDF that is mostly text is already small and has little left to compress.
How can I compress a scanned PDF?
A scanned PDF is a series of page photos, so it shrinks the most. Add it to DockFlip Compress PDF and choose Recommended or Extreme. In our test, Recommended cut a 9.29 MB scan to 2.07 MB and Extreme to 840 KB, and the text on the page stayed readable.
How do I compress a PDF for email?
Gmail allows attachments up to 25 MB and Outlook.com up to 20 MB, but many companies and forms set a lower limit. Compress to Recommended, and try Extreme if the limit is strict. You can also send several smaller PDFs instead of one large one.
Is it safe to compress a PDF online?
It depends on the tool. Many sites upload your PDF to their server. DockFlip compresses the PDF inside your browser, so the file stays on your device. That suits contracts, ID scans and bank statements.
Is DockFlip Compress PDF free?
Yes. There is no signup and no watermark. Each file can be up to 100 MB, and you can add several PDFs at once.
DockFlip Team. We build free image and PDF tools that run in your browser. The size tests in this guide use three sample PDFs we built, run through DockFlip Compress PDF, and results vary by file. Last updated on .