A document that’s mostly text should be a few hundred kilobytes. When a .docx turns up at 30 or 50 MB, something specific is inside it. Here’s the list, roughly in order of how often it’s the culprit.
1. Full-resolution images
By far the most common cause. Paste a photo from a modern phone into Word and you’ve embedded a 12-megapixel, 6 MB image — even though it displays as a 3-inch-wide picture. Word keeps the original data, not the size you see. Ten of those and you have a 60 MB document.
Fix: Compress the Word document. The embedded images are re-encoded at a sensible size while your text and layout stay exactly where they are.
2. Screenshots saved as PNG
PNG is lossless, which is great for crisp UI screenshots and terrible for file size — a full-screen PNG can be several megabytes where the equivalent JPG is a few hundred kilobytes. A manual full of screenshots gets heavy fast.
Fix: same as above; compression converts them to a sensible encoding.
3. Cropped images that aren’t really cropped
Cropping in Word hides the parts you cut off — it doesn’t delete them. A photo cropped down to one corner still carries the whole original inside the file.
Fix: compressing the document discards the hidden data along with the excess resolution.
4. Tracked changes and version history
A document that’s been through several rounds of review carries every revision, every comment, and every deleted paragraph. This is invisible until you look at the file size.
Fix: in Word, accept or reject all changes and delete resolved comments before sharing. This is worth doing for privacy as much as for size — old tracked changes reveal things you may not want to send.
5. Embedded objects
An embedded Excel sheet, a pasted chart, or a linked presentation stores the whole source file inside your document. One embedded workbook can add tens of megabytes.
Fix: paste as a picture instead of an object where you only need to show the data, or keep the spreadsheet as a separate attachment.
6. Embedded fonts
“Embed fonts in the file” in Word’s save options adds every font used, and if “embed all characters” is ticked, the entire character set — including thousands of glyphs you never typed.
Fix: turn it off unless you’re sending to a print shop. If layout fidelity is the real goal, convert to PDF instead — a PDF embeds only the characters actually used and locks the layout properly.
The quick decision
- Sending it for review or editing? Compress the Word document and send the .docx.
- Sending it as a finished document? Convert it to PDF and compress that if needed — usually smaller than the .docx and it can’t be accidentally edited.
- Still too big for email? Split the content, or send a PDF and split it into parts.
One note: a legacy .doc file is normalised to the modern .docx container when you compress it, which is part of why it gets smaller. The content and formatting come across unchanged.
Ready? Try the free Compress Word tool now — no sign-up, no watermark, and your file is never stored.