How to compare two Word documents
Word's Compare feature does this properly, and for a whole document it is the right tool. Here is how to use it and what to watch for.
Word has a built-in comparison feature, and for two versions of a whole document it is the right tool: it works on the files themselves, so it sees numbering, styles, tables and everything else that never survives being copied out.
The steps
- Open Word. You do not need either document open — Compare works on files.
- On the Review tab, choose Compare, then Compare again from the menu.
- Set Original document to the earlier version — the one you sent — and Revised document to the one that came back. Getting these the wrong way round inverts every insertion and deletion in the result.
- Put your name or the other side's in Label changes with, so the revisions in the result are attributed to something meaningful.
- Open More to reach the options below, then click OK.
The steps are the same in Word for Mac, on the same Review tab. The dialog is laid out a little differently and the options are the same ones.
What the options do
Two of the options in More change the result enough to be worth setting deliberately.
| Option | What it does | Suggested |
|---|---|---|
| Show changes at | Word level marks whole words as changed; character level marks the individual letters that differ. Character level is precise and, on a paragraph that was rewritten, produces something close to unreadable. | Word level |
| Show changes in | Whether the comparison is written into one of your documents or into a new one. | New document |
| Comparison settings | Which categories of difference to report: formatting, white space, tables, headers and footers, and so on. | Leave all on |
Turning formatting off is tempting, because formatting changes are noisy. Resist it on a document you are checking before signature: a paragraph that quietly became part of the preceding clause is a formatting change, and it can move a limitation from one place to another.
Reading the result
Word opens the comparison as a new document, usually alongside a Revisions pane listing every change, and small windows showing the two source documents. The panes scroll together.
The comparison itself is a document with tracked changes in it. You can accept and reject revisions in it, which makes it a useful place to work, but it is a new file: changes you accept there do not appear in either original.
The Revisions pane is the fastest way to see the shape of a turn. A count of 300 on a document that was supposed to come back with two changes tells you something before you have read a word of it — usually that the other side worked from an older version, or that a style changed.
What to check
- That the two documents are the ones you think they are. Check the filenames in the dialog rather than trusting the folder.
- Numbering. Automatic numbering renumbers silently. A clause that is now 8.3 rather than 8.2 may show as unchanged text in a different place, and every cross-reference to it needs checking.
- Moved text. Word reports a moved paragraph as a deletion in one place and an insertion in another. Read both halves before concluding something was cut.
- Schedules and annexes. They are often maintained separately and are the most common place for two versions to diverge without anyone noticing.
When Compare is not there
Compare is a desktop feature. Word on the web does not have it at the time of writing, and neither do the mobile apps, so a document opened from a link in a browser cannot be compared where it sits — you need the desktop application and both files.
If you do not have desktop Word at all, other applications can produce a comparison, with limits worth knowing in advance.
For smaller jobs
All of the above is right for a document. It is a lot of process for a clause somebody pasted into an email, where saving two files in order to compare them is most of the work. For that, compare the text directly — and then go back to Word for anything that has to be handed over as a file.