Why is my PDF so big? File size explained

A three-page PDF has no business being 40 MB. When it is, something specific is bloating it — and each cause has a fix.

The usual suspects

• High-resolution scanned pages stored as full-quality images.
• Photos pasted at camera resolution instead of screen resolution.
• Full fonts embedded instead of subsets.
• Leftover revisions kept via incremental saves.

A quick diagnosis

If the file is mostly scans or photos, it is an image problem — re-compress. If it is text-heavy yet huge, it is likely fonts or accumulated save history — re-save cleanly.

The fastest fix

Re-encoding the pages usually cuts size dramatically with little visible loss.