How to Reduce PDF File Size – 5 Tips to Keep It Readable

A PDF’s size is mostly determined by the images inside it. A text-only PDF is often a few hundred KB even with dozens of pages, while these tend to be large:

• PDFs with photos taken on a smartphone (one photo can be several MB)
• Documents scanned in color or at a high resolution
• Documents with many pages
• PDFs with embedded font data

So the most effective way to reduce size is to make the images smaller.

If there’s a limit such as “2MB per file”, use that number as your target. Going much smaller than needed only lowers quality.

Our Compress PDF tool lets you enter a target such as 500KB, 1MB or 2MB and compresses the photos and scans inside to fit. Your file is never uploaded; it’s processed on your device.

Removing blank or unneeded pages reduces the size, and with fewer pages, each one gets more of the size budget, so quality holds up better.

Text documents and materials where color doesn’t matter can get smaller in grayscale. It’s also useful when an office asks for black-and-white documents.

Long documents sometimes can’t fit the limit. Check whether you can submit several files, and if so, split the PDF by document.

If you haven’t made the PDF yet, start small:

• When scanning, choose grayscale or black and white instead of color, at about 200–300 dpi
• When saving a PDF from Word or Excel, choose “Minimum size (publishing online)”
• Shrink photos with Compress Images before turning them into a PDF

Windows has no built-in PDF compression. On a Mac, Preview’s File → Export with the “Reduce File Size” Quartz filter makes a PDF smaller, but you can’t choose a target size and quality often drops a lot. The free Adobe Acrobat Reader can’t compress either; you need paid Acrobat Pro.

Before submitting, check that small text, numbers and photos are still readable. Lost quality can’t be restored, so keep the original file too.