June 20, 2026
How to Make a PDF File Smaller
Large PDFs slow down email, cloud uploads, and page loads. Here are the most effective ways to reduce PDF file size — and why each technique works.
Why PDFs Are Large
Images are almost always the culprit. Embedded photos at full camera resolution, scanned pages at 600 DPI, or design files with unoptimised graphics can push a short document past 50 MB. Text alone is tiny — a 100-page text document is usually under 500 KB.
Compress the Images Inside the PDF
The fastest method: upload to Papyrio's Compress PDF. Ghostscript resamples embedded images from their original resolution down to screen-optimised resolution. Image-heavy PDFs typically shrink 30–70%. Text quality is completely unaffected. The process takes a few seconds and requires no software.
Convert to Grayscale
Color images are larger than grayscale images. If the document doesn't need color — a scan, a text report, a black-and-white diagram — converting to grayscale using Grayscale PDF removes all color data. Combined with compression, this can cut file size dramatically.
Split the PDF and Keep Only What You Need
If you only need to share part of the document, split it first. Upload to Split PDF, download the ZIP, and extract only the pages that matter. Sending a 3-page excerpt instead of a 40-page report is faster for everyone.
When Compression Doesn't Help Much
Text-only PDFs, PDFs already optimised by another tool, and PDFs containing vector graphics rather than raster images won't compress significantly. For these files, the limiting factor is content, not image resolution. Splitting into smaller sections is the only effective reduction strategy.