Reduce PDF File Size Online

Make an oversized PDF smaller without losing readability, ideal for email limits and uploads. Upload, compress, download. No signup, no install.

Go to tool

Why your PDF is large

Scanned PDFs are large because each page is stored as a full-resolution image. A single A4 page scanned at 300dpi produces an image file around 1 to 3MB. Scan 50 pages and you are looking at 50 to 150MB before the file even reaches you. PDFs exported from Word, Excel, or PowerPoint also tend to bloat because the application embeds a preview thumbnail for each page alongside the actual content, plus font subsets and metadata that accumulate with every save. In both cases, most of that extra data can be stripped without changing what you see on screen.

What happens during compression

Compression reduces image resolution to screen-appropriate levels, typically around 150dpi, which is enough for reading on any monitor or display. It also strips embedded thumbnails, redundant metadata, and duplicate resource objects that accumulate in files that have been opened and re-saved multiple times. Text in PDFs is stored differently from images and uses its own compression that is already lossless, so any readable text in your document stays exactly as sharp as before. Fillable form fields are preserved. What changes is purely image quality, and only at resolutions higher than what your screen can show anyway.

How much your file will shrink

Results depend almost entirely on what the file contains. Scanned documents typically shrink by 60 to 80 percent. A 50MB scanned contract often comes back as 8 to 12MB. PDFs exported from Microsoft Word or Excel usually shrink by 10 to 30 percent because the embedded images are already reasonably compressed. PDFs downloaded from websites or generated by printer drivers sometimes shrink very little, because the originating software already applied compression during export. If your file barely changes, the content was probably already near-optimal and there is not much left to remove.

When screen quality is not enough

For most workflows, 150dpi images are fine. Email attachments, shared documents, online forms, digital archives, everything reads well on screen at that resolution. The exception is print. If the compressed PDF is going to a print shop or a copier that will produce physical copies larger than A5, check the output before sending. Zoom into the compressed version and look at photographs, charts, and any signatures or stamps. If they look soft at 100 percent zoom, the original was probably a scan and the compressed version will print slightly blurry at larger sizes. Legal and regulatory submissions sometimes specify minimum resolution requirements; check those before compressing for that use case.

What to do after downloading

Open the compressed file before you do anything else. Scroll through a few pages and zoom in on at least one image-heavy section. If the document contains signatures, stamps, tables, or diagrams that need to stay legible, give those a close look. If you are sending the file to a printer, print one test page first. If the file is still too large after compression, the most common next steps are removing blank pages, splitting the document into separate files for different recipients, or running OCR on a scanned document and saving as a text-based PDF rather than an image-based one. A text-based PDF with embedded fonts is almost always smaller than an image-based scan at the same apparent quality.

Why some files barely shrink

If your PDF shrank by less than five percent, one of a few things is likely: the images inside were JPEG files that were already compressed when the PDF was created; the file was generated by a system that applied its own compression during export; or the PDF was scanned from a photocopy, meaning the source was already degraded before it became a PDF. In these cases, compressing again adds very little. The more practical options are removing unnecessary pages, reducing the number of embedded fonts, or splitting the document so you only send the sections the recipient actually needs.

Before you compress: quick checklist

Check the size limit for where you are sending the file. Most email servers cap attachments at 10 to 25MB; some upload forms are much stricter.
If the PDF has fillable fields, verify they still work in the compressed version before distributing.
For print use: zoom to 100 percent in the compressed file and check that images and signatures are still sharp enough.
If the file is still too large after compression: remove blank pages first, then compress again.
For legal or regulatory submission: confirm the minimum resolution requirement before compressing.

Frequently asked questions

How much will my PDF shrink?

Scanned documents typically shrink by 60 to 80 percent. PDFs from Word or Excel usually shrink by 10 to 30 percent. PDFs that were already optimized may shrink by less than 5 percent. The result depends on what is inside the file.

Will the text stay readable after compression?

Yes. Text in PDFs uses lossless compression and is not affected. Only embedded images are downsampled. Letters, numbers, and any vector graphics stay exactly as sharp as in the original.

My compressed file barely got smaller. Why?

The images in your PDF were probably already compressed when the file was created. This is common with PDFs downloaded from websites, generated by printer drivers, or produced by software that applies its own compression during export. There is not much left to remove in those cases.

Is the original file deleted after I download?

Yes. Files are stored temporarily during your session and deleted automatically within two hours. Nothing is retained after that.

What size should I aim for when sending by email?

Most email servers accept attachments up to 10 to 25MB, but corporate mail filters are often stricter. Aiming for under 10MB covers most cases. If the compressed file is still too large, consider splitting it or sending a download link instead.

Helpful pages

Trust checks and reference pages for this scenario.