Compress PDF
Shrink file size by recompressing images while keeping text sharp.
Reduce PDF file size so it fits an email or an upload form. ModifyPDF recompresses and downsamples embedded photos, removes unused data, and leaves text and vector graphics untouched. Need a specific size? Choose “Target file size” and type the limit, for example 100 KB, 200 KB or 1 MB.
How to compress a PDF
- Choose the PDF to compress.
- Pick Extreme, Recommended or Less compression, or choose “Target file size” and enter a limit in KB.
- Click “Compress PDF” and download the smaller file.
Frequently asked questions
Can I compress a PDF to a specific size, such as 100 KB or 1 MB?
Yes. Choose “Target file size”, pick 100 KB, 200 KB, 300 KB, 500 KB, 1 MB or 2 MB, or type any limit in KB. ModifyPDF tries several quality settings and keeps the best-looking result that is under your limit.
How much smaller will my PDF get?
It depends on the content. Image-heavy files often shrink by 50–90%. Text-only files are usually already small.
Will text become blurry?
No. Only embedded images are recompressed; text stays crisp and searchable.
Are my files uploaded to a server?
No. ModifyPDF processes files with JavaScript inside your browser. Your documents never leave your device, and nothing is stored after you close the page.
Compress to a target size
Upload forms often set a hard limit such as 100 KB, 200 KB or 2 MB. Choose “Target file size”, enter the limit in KB, and the tool finds the best quality that fits. If reducing the images is not enough, pages are saved as images so the limit can still be met, and a note tells you when that happened.
Compression levels
Recommended resamples images to 150 dpi at their printed size, which looks sharp on screen and in normal printing. Extreme goes down to 72 dpi for the smallest possible file. Less compression keeps every image at full resolution and only re-encodes it with high JPEG quality.
What changes and what doesn’t
Only images are recompressed. Text, fonts and vector graphics are kept as they are, so text stays sharp and searchable. PDFs made mostly of text are already small and may shrink very little; scanned documents and photo-heavy files shrink the most.
Why PDFs get big
File size usually comes from images: scans saved at high resolution, photos pasted into documents at full camera size, or graphics stored without compression. A ten-page scanned document at 600 dpi can easily exceed 20 MB, while the same pages at 150 dpi are a fraction of that and still easy to read.
Common size limits
Many email services cap attachments at around 20 to 25 MB, and online application and government forms often accept only a few megabytes per file. Our guide to compressing a PDF for email walks through the options step by step.
Choosing a level
Start with Recommended. Use Extreme only for documents that will be read on screen, as fine print in scanned pages can become harder to read at 72 dpi. Keep an original copy if you may need to print the document later.