How to compare the differences between PDF files and Word documents

Key points of this article

Compare directly when the formats are different. Typesetting differences will produce a large number of false changes. It is more reliable to unify them into the same format first and then compare them.
When Word is an editable source file, you can save it as PDF and then compare it with the PDF sent by the other party.
The scanned PDF does not have selectable text, so OCR recognition must be performed before comparison, otherwise the result will be incomplete.
The comparison results can only be used as clues, and key contents such as numbers, dates, tables, and formulas need to be manually checked one by one.

If you have a PDF contract or paper in your hand, and the other is a revised Word draft, and you want to find out what has been changed between the two, it is easy to miss it by looking line by line with the naked eye. Many people search for "how to compare pdf files with word documents" and encounter this situation of different formats. Most common comparison tutorials only talk about how to compare two PDFs or two Words, but few people explain the cross-format scenario clearly.

This article is written for those who need to check document changes, including those who review contracts, revise papers, and proofread reports. After reading, you will be able to judge which side should be converted into which format, know how to compare after conversion, and know how to check the comparison results item by item.

How to compare PDF and Word? One sentence conclusion

When the formats are different, it is directly easier to mark a large number of non-existent changes due to different fonts, pagination and margins. A safer approach is to make the formats on both sides consistent first and then compare. The table below gives suggestions based on the documents you have on hand.

your situation	Recommended practices	reason
Word is the editable source file, and PDF is the final version sent by the other party.	Save Word as PDF and compare the two PDFs	The version issued by the other party shall prevail, there are few layout differences.
PDF is a scan or image	First do OCR to identify the text, and then compare	The scanned document does not have a text layer and cannot be compared directly.
Only care about text changes, not about typesetting	Convert PDF to Word and compare the two text contents	Text comparison is cleaner and layout changes can be ignored
The file contains a large number of tables, formulas or charts	Manually review these sections page by page after comparison	Conversion may change table structure and formula display
Very few pages, only a few changes	Read side by side and mark manually	Manual verification of several changes is often faster than tools

Before you start: Confirm these points first

Confirm which version is the base version. The direction of the comparison results depends on who is the "old version" and who is the "new version". Decide on it first to avoid inverting the old and new, otherwise all the additions and deletions will be read backwards.
Determine whether the PDF is a scanned copy. Use your mouse to select a piece of text in the PDF and copy it. If the selection cannot be selected, or the copied text is garbled, it usually means that it is a scanned copy or picture text and needs to be identified first.
Check page count and pagination. When there is a large gap in the number of pages on both sides, first confirm whether there is no cover, attachments or headers. Missing pages will cause all subsequent differences to be misaligned.
Back up original files. Conversion and comparison will generate new files, leaving the originals intact, making it easier to refer back to them later and avoid overwriting by mistake.
Confirm that the file has no permission restrictions. Files that are encrypted or restricted for editing may not be opened, converted, or exported. You need to obtain the corresponding permissions before proceeding.

Steps to convert and compare PDF and Word in OmniDoc

The following steps are based on "after converting Word to PDF, use the PDF comparison function to compare". If your benchmark is PDF, you can use the conversion to Word route in the "Core Comparison" later.

If you have a scanned PDF, first perform OCR in the PDF editor of the OmniDoc desktop client to identify the text in the image into selectable text for subsequent comparison.
Open the Word file in office software and save it as PDF to get a file in the same format as the other party's version.
Open the OmniDoc desktop client (available for download at download.omnidoc.top) and find the function entry for comparing two PDF files.
Add two PDFs in sequence, one as the baseline version and one as the version to be verified. Be careful not to put them upside down.
View the comparison results and record the added, deleted or modified text point by point.
Organize the list of changes into a document and save it with the original file for easy traceability in the future.
For pages where tables, formulas, and pictures are located, open the original files and review them manually. Don’t just look at the comparison results.
After confirming that it is correct, send the conclusion or revised document to colleagues or the other party.

Check each item after completion

After the comparison results come out, do not directly treat them as final conclusions. The following suggestions should be checked one by one.

Check item	What do you think?	What if there's a problem?
Whether the text changes are complete	Compare a few paragraphs with the original to see if there are any sentences left out	The scanned parts are re-OCR first and then compared again
Number, date and amount	Check the figures of the changes one by one	Manual confirmation of digital changes, do not only rely on the comparison results
Tables and formulas	Open the original page for comparison	Manually correct the conversion result based on the original document
Page number and paging	See if the differences are concentrated in the pages.	Re-compare after unifying the font or margins to eliminate false differences
Machine-recognized and converted text	Focus on checking text paragraphs and proper nouns	There may be errors in identification and conversion, and important contents need to be checked word by word.

# Core comparison

According to the purpose of the file, there are three common practices, each with an appropriate scenario.

Method	What situation is suitable for?	Major limitations
After converting Word to PDF, compare PDF.	The other party gave the final version of PDF, and you need to check the overall changes to the layout and text.	If typesetting is inconsistent, there will be more false differences.
Compare the text after converting PDF to Word	Only care about the text content, hope to ignore the layout change	The layout will change after conversion, and tables and formulas may need to be revised.
Side by side manual reading	Short space, few changes, or a large number of charts in the document	It is easy to miss when the length is long, but it takes more time.

# frequently asked questions (FAQ)

1. Can the scanned version of PDF be directly compared with Word?

There can be no direct comparison. The scanned piece has no selectable text layer, so you need to do OCR recognition first, get the text that can be selected, and then convert or compare.

2. The format has changed after converting PDF to Word. Can you compare it?

You can compare text content. However, the font, paging and table structure may be changed, the comparison should be text-based, typesetting differences should not be regarded as actual changes.

3. Why are so many areas that have not been changed in the comparison results also marked?

Common reasons are inconsistent margins, fonts, segments, or headers. After a unified format, most of the false differences will disappear.

4. Can the comparison results be directly used to make a formal conclusion?

Direct use is not recommended. There may be errors in identification and conversion. Numbers, dates and proper nouns should be checked manually and used in formal situations after confirmation.

# Summary

PDF and Word format is different, first unified into the same format and then compared, is the key to solve the problem of "how to compare pdf files with word documents". After the conversion, the comparison results are used to locate and change, and then the numbers, tables and formulas are manually checked item by item, and the conclusion is reliable.

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