Email a large PDF
Many email providers limit attachments to 25 MB — compress to fit.
Compress PDF
Reduce the file size of a PDF without sacrificing readable quality. Useful when a PDF is too large to email, too slow to upload, or needs to fit a portal's size limit. Choose between low, medium, or high compression depending on how aggressive you want the optimisation to be.
How to use Compress PDF
- Upload your file using the secure uploader.
- Choose any available conversion options, such as page size, margins, quality or language.
- Start the conversion and download the finished file when it is ready.
Common use cases
Upload to a web portal
Some upload forms cap PDFs at 5 or 10 MB — high compression usually solves it.
Share over WhatsApp or messaging apps
Reduce a multi-MB PDF to something that sends quickly on mobile data.
Save storage on your computer or cloud
Compress old PDFs in bulk to free up space without losing content.
Limitations
Conversion results can vary depending on the structure, quality and complexity of the source file.
Privacy and security
Files are transferred over HTTPS, processed only for the requested conversion and automatically deleted within 30 minutes. FlowToPDF does not require an account and does not use uploaded files for training or manual review.
Frequently asked questions
How much can I compress a PDF?
It depends on the PDF. Image-heavy PDFs can shrink 50–80%. Text-only PDFs often shrink less because text is already compressed.
Will compressing reduce the quality of my PDF?
Low compression is essentially lossless. Medium and high re-encode embedded images at a lower quality, which may be visible if you zoom in.
Does compressing affect text quality?
No. Text remains crisp at all compression levels because it is stored as vectors, not images.
Can I compress a password-protected PDF?
You need to unlock it first using our Unlock PDF tool, then compress.
Is there a limit on PDF size?
Up to 50 MB per file. Larger PDFs should be split first.
Related PDF tools
Convert your file
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