How to Compress a PDF Without Losing Quality
To compress a PDF for free, upload it to myoffice, open the file's menu, choose PDF Tools…, then Compress, and start the job. myoffice re-saves the PDF with more efficient internal compression and creates a new file next to your original. It is lossless: text, images and layout look exactly the same. You need a free account and nothing to install.
Because it is lossless, the saving depends on the file. This guide explains what to expect, why some PDFs barely shrink, and what to do when you need a much smaller file.
How do I compress a PDF?
- Sign in or create a free account, then upload the PDF (up to 50 MB).
- Open the file's ⋮ menu and choose PDF Tools….
- Select Compress. There are no settings to choose.
- Start the job. A new file named like
report (compressed).pdfappears in the same folder. - Compare the two sizes in the file list and keep whichever you prefer.
What does lossless compression actually do?
A PDF is a container of objects: text, fonts, images and page descriptions. Some are stored inefficiently, for example data that was not compressed, or objects that can be packed together more tightly. The compress tool re-writes the file so that this internal data is compressed more efficiently.
What it does not do is change your content. It does not reduce image resolution, does not re-encode photos at lower quality, and does not remove anything. That is why the result is visually identical to the original.
Why did my PDF barely get smaller?
Lossless compression can only remove wasted space. If there is little wasted space, there is little to gain:
- Scans and photo-heavy PDFs. Most of their size is the image data itself, which is already compressed. A scanned 100-page document will not shrink much.
- PDFs that were already optimised. Files exported from a modern application or already compressed by another tool have little left to squeeze.
- Embedded high-resolution images. These dominate the file size, and lossless compression leaves them as they are.
PDFs that were saved inefficiently, such as some exports and files that have been edited many times, tend to shrink the most.
How can I get a much smaller PDF?
When lossless is not enough, the size has to come from the images, and that means choosing a trade-off:
- Re-scan at a lower resolution. For reading on screen, 150 DPI is often enough. 300 DPI is only needed when text must survive printing or OCR.
- Remove pages you do not need. Use Remove pages or Extract to drop cover sheets and blank pages.
- Split a large file into parts and send them separately.
- Rebuild from smaller images. Convert the pages to JPG and turn the images back into a PDF after reducing them in an image editor. This lowers quality, so keep the original.
Compress, then check
- Open the compressed file and scroll through it once.
- Keep the original until you are sure the new file is what you want.
- If you plan to password-protect the PDF, compress first, then protect, so the tool can work on the file structure.
Frequently asked questions
Does compressing reduce the quality of my PDF?
No. This compression is lossless, so text and images are unchanged.
How much smaller will my PDF get?
It depends on the file. Inefficiently saved PDFs can shrink noticeably, while scans and photo-heavy files may barely change.
Does it change my original?
No. Compress creates a new file and leaves the original as it is.
Is there a size limit?
Each uploaded file can be up to 50 MB, and everything counts against your storage quota (a reminder at 100 MB, blocked saves at 250 MB on the free plan).
Can I compress several PDFs at once?
Run the tool on each file. You can also merge PDFs first if you want one combined, compressed document.
Try it
Create a free account, upload a PDF and compress it. Compare the two sizes and you will see straight away how much of your file was wasted space.