How to compare two versions of PDF contracts and find out the changes

Key points of this article

Unify the version naming before comparison, and store the files returned by the other party separately to avoid comparing the wrong files.
First confirm whether text can be selected in the PDF; the scanned document must be OCRed first and then compared.
The comparison results can only tell you what has changed. The amount, date, and clause number still need to be manually checked item by item.
For changes in tables, attachments and footers, the comparison results may not be complete, so you need to turn the page to confirm.
After finalizing, issue a signature request and keep the issued version for easy traceability later.

When the contract was revised to the third version, the other party said, "Only a few changes were made." You opened the two PDFs and looked at them page by page. After reading for half an hour, you still felt uneasy. This is a headache for many people before issuing a contract: before signing, it is necessary to determine what changes have been made between this version and the previous version.

This article is written for business leaders, administration and small team leaders who need to send out contracts for signing. If you are searching for how to use the document comparison tool online, here we will explain how to use OmniDoc's PDF comparison function to find the differences between the two versions of the contract, and then send the confirmed version for signing. After reading, you will get a set of fixed procedures, and know where things are easily missed and how to review them.

How to compare the two versions of the contract so that no changes are missed? One sentence conclusion

Use the PDF comparison function to list the differences, and then manually check the numbers, dates, amounts and term numbers to confirm that they are correct before issuing a signature.

your situation	Recommended practices	reason
Both versions are PDFs where text can be selected.	Use the comparison function directly in the OmniDoc desktop client	Text can be read and differences can be listed by content
One of the versions is a scanned copy	Do OCR first, then compare	Text in scanned images cannot be directly compared
Changes focus on amounts, dates, and numbers	In addition to comparing the results, manually check each item	Changes in small numbers are easily overlooked
The contract amount is large or involves legal liability	Compare and then submit it to legal counsel or experienced colleagues for review.	Comparison can only explain what has changed, but cannot judge whether the changes are appropriate.
The other party needs to sign online	After finalization, issue with signature request	The version must be finalized before signing and cannot be changed at will after it is issued.

Scenario: The other party returns the revised draft, with a postscript stating only two changes.

You are the business leader of a small company and have negotiated two rounds of service contracts with customers. The first version has been sent to the other party, and the other party responded with a revised PDF, with the postscript stating "Only the payment method and liquidated damages have been changed." You have three documents in hand: your original version, the other party's returned version, and the final version required internally. The contract needs to be sent out for signing before get off work today.

The problem is that the actual changes made by the other party may be more than the few mentioned in the postscript. Terms are sometimes tweaked in subtle ways, such as a deadline changing from 30 days to 15 days, or an attachment missing one page. It is difficult to ensure that everything is found by comparing page by page with the naked eye.

Complete process

Name them uniformly and store them separately. For example, "Service Contract_v2_Original" and "Service Contract_v2_Other Return", the files returned by the other party are placed in a separate folder to avoid getting the wrong version during comparison.
Check whether the text can be selected. Drag and select a section of text in the PDF. If you can select it, it will be a text version; if you cannot select it, it will be a scanned copy and you need to do OCR first.
Use the comparison function in the PDF editing function in the OmniDoc desktop client to add the two PDFs separately and start comparing.
Check the differences item by item and divide them into three categories according to their nature: substantive terms (payment, liquidated damages, time limit, scope of liability), numbers and dates, wording and format. Substantive provisions shall take precedence.
Manually check the comparison results: turn to the page where each difference exists, read the context and make sure the meaning does not deviate.
Also read the parts not listed in the comparison results. Changes to cells, attachments, headers and footers in the table must be confirmed by turning the page yourself, and the number of pages and attachments in the two versions must also be corrected.
If correction is needed, use the PDF editing function to modify the text of the paragraph, change the unacceptable changes back to the original text, and then save it as a new version. The file name will be updated with the version number simultaneously. After the final draft, you can export it to Word to facilitate internal annotation.
Use the signature request function to send the final PDF to the other party to sign online, and keep this version of the document to facilitate future verification of which version was signed at that time.

Where things can easily go wrong

Versions are mixed up. The method of discovery is to check whether the file name, page number and date in the file are consistent with your correspondence records. The solution is to mark the source of each file before comparing, and do not compare directly in the download directory.
Scan comparison results rarely or do not match. The method of discovery is that the comparison result is obviously inconsistent with the difference you see with the naked eye. The solution is to OCR first and then spot check the identified numbers and clause numbers. OCR may recognize typos. Important content must be manually changed back to the original text and checked again.
Only look at the comparison results, and miss out on content not listed. Typical cases include attachments, tables and footers. The solution is to compare and at least read through the contents and attachments of both versions.
I forgot to update the version after making the changes. If the version the other party sees when signing is inconsistent with what you discussed, disputes will arise. Each modification is saved as a new version, and the file name and page number are checked before sending.
Use online comparison sites to process contracts. Contracts often contain sensitive information. Before choosing a tool, you should check the file size limit, whether the uploaded file is saved, the privacy terms, and whether the layout is retained. Do not upload it casually.

🎯 Which method is suitable for you?

If you handle contracts alone, not many versions

Follow the above process, use the comparison function to list the differences, and then manually check them one by one. Usually no additional tools are needed.

If you often receive revisions from the other party

First, fix the naming and storage rules, conduct a complete comparison each round, and record the differences in each version to facilitate later tracing who changed what.

If the contract amount is large or involves legal liability

Comparisons are only used to locate changes; conclusions should be left to legal counsel or lawyers for judgment. Don't sign off solely based on comparison results.

If one of the copies is a scanned copy signed on paper

First, perform OCR, then compare, and randomly check the recognition results. The signatures and seals in the scanned copy do not become comparable text and require manual confirmation.

❓ Frequently Asked Questions (FAQ)

1. Can the comparison function directly determine which changes have legal effect?

No. The comparison only lists differences in text and positioning; whether the changes are appropriate and carries risks should be judged by legal counsel or lawyers.

2. The two documents have different page counts. What should you pay attention to when comparing?

When the number of pages differs, first confirm whether the page was added or deleted, then compare the results. This makes it easier to determine which part of the content was adjusted.

3. What should I do if the other party sends me a Word, not a PDF?

First, convert both versions into PDF and then compare. After conversion, check whether the layout, tables, and page numbers match the original text to avoid misjudgments caused by formatting changes.

4. After comparison, should you reinitiate and sign again?

As long as the contract content changes, the final version should be used for re-signing, and the previous request should not be retained.

5. Can free online comparison websites be used to process contracts?

If the contract contains sensitive information, confirm file size limits, whether files are saved, privacy terms, and formatting before use. Do not upload if unsure.

📝 Summary

The key to comparing the two contracts is to first unify the versions, then use the PDF comparison function to list the differences, and finally manually verify and submit them to relevant personnel for review. After finalization, it is sent online for signature, and the published version is kept so that changes can be traced.

Open OmniDoc and use the PDF editor to process your files