How to Reduce a PDF's File Size in Acrobat (Without Wrecking Quality)

Your PDF is too large to attach or upload, usually because it’s packed with high-resolution images or embedded fonts.

Why: Acrobat can resample and recompress those images, unembed fonts, and strip out invisible junk (old bookmarks, thumbnails, metadata) to cut the size — often dramatically — while keeping the document readable.

Fix 1: One-click compress (fastest)

1. Open the PDF and choose All tools > Compress a PDF.
2. Acrobat compresses and reports the new size. Save the result.

This is the quickest route and is enough for most “too big to email” cases.

Fix 2: Reduced Size PDF

For a quick reduction with a compatibility choice:

1. Choose Menu (or File) > Save as Other > Reduced Size PDF.
2. In the dialog, pick a version from Make compatible with (newer versions compress more aggressively).
3. Click OK and save under a new name.

This resamples and recompresses images, removes embedded Base-14 fonts, subset-embeds the rest, and compresses the document structure.

Fix 3: Optimized PDF (full control)

When you need to target a specific size or protect image quality:

1. Choose Menu (or File) > Save as Other > Optimized PDF.
2. Start from the Standard preset, then adjust:
   • Images — downsample and compress (the biggest win for photo-heavy files).
   • Fonts — unembed or subset fonts you don’t need exactly matched.
   • Discard Objects / Discard User Data / Clean Up — drop thumbnails, comments, metadata, and invalid bookmarks.
3. Watch the size estimate, then save.

FAQ

How much smaller will it get? Scanned or image-heavy PDFs often drop 50–80%; a text-only PDF that’s already small won’t shrink much.

Will compression blur my images? Aggressive downsampling can soften photos. Use Optimized PDF (Fix 3) and keep image resolution around 150–200 dpi for screen, 300 dpi for print.

Don’t see Compress a PDF? Update Acrobat (Menu > Check for Updates); older builds put it under Tools > Optimize PDF.

Sources: Adobe — Reduce PDF file size, Adobe — Reduce PDF file size with advanced options