Compare Contract Versions. What Changed in the Revised PDF?
To compare a revised contract with an earlier version, first choose the original you want to use as your baseline. Compare the two text-based PDFs, read the added, removed and changed wording, then check the relevant passages in both source files before separate human or legal review.
Logrun Lab compares extracted text. It does not read text in images or scans, compare page appearance, or interpret legal meaning. Text on one page does not mean that every page or appendix is covered. Check that the passages and attachments you need to compare have usable text.
Choose the baseline and keep the direction clear
Use Original PDF for the specific earlier version you want to compare against, and New PDF for the revised copy. Confirm the pair from your version records or correspondence. A filename or date alone does not establish which draft you intended to review.
Added means a text block appears on the New PDF side without a matched block on the Original PDF side. Removed means the reverse. Changed means the tool paired two text blocks and shows differences within them. These labels describe the comparison, not the importance of a clause or who made an edit.
Swapping the inputs reverses the direction. In our controlled example, the removed Storage item becomes Added, and the added Incident reports item becomes Removed.
Read the wording behind a change count
We compared two synthetic, two-page contract PDFs using Logrun Lab’s current text-comparison code. The result was 3 Changed, 1 Added and 1 Removed text blocks. These counts describe this example. They are not an accuracy score or a count of legal risks.
3. Payment. The customer will pay each invoice within 30 days after receiving the invoice.
3. Payment. The customer will pay each invoice within 45 days after receiving the invoice.
Read the whole sentence as well as the highlighted number. In this example, the payment wording changes from 30 to 45 days after receiving the invoice.
The other Changed blocks show USD 1200 becoming USD 1500 and the word “not” being added to the assignment wording. The Storage item is Removed. An Incident reports item is Added. A small highlighted token and an entire added block both need to be read in context. The tool does not decide their legal effect.
This example comes from a controlled test of synthetic PDFs with extractable text. It illustrates the comparison result, not a real agreement or a guarantee of finding every change.
Check both source pages before writing a review note
Use the Previous and Updated page references to locate each passage in the two PDFs and read the surrounding text. A revised document may place the passage on a different page. In our assignment example, the Previous passage is on Page 1 and the Updated passage is on Page 2. The word “not” was also added.
Keep your own review note outside the tool. Identify the two versions, record the page in each, copy the exact before-and-after wording, and write the question you want a reviewer to address. Name the person who should review it. Logrun Lab PDF Compare does not create or export that note, assess risk, or recommend whether to sign.
Zero text changes does not mean identical PDFs
A zero result means that the comparison found no changes in the normalized text blocks it compared. It does not prove that the complete PDF files are identical.
A version with the same wording but different line wrapping and a different page break produced 0 text changes. A separate pair with identical text on one page and a changed amount in an image-only appendix also produced 0 text changes. The appendix amount changed from 1200 to 1500, but its text was not extracted.
A completely image-only PDF was rejected because no usable text layer was found. A mixed PDF can still be accepted because text exists elsewhere in the file. Acceptance does not establish coverage of every relevant page.
Check the relevant pages and attachments in both originals. Obtain text-based source versions for passages that exist only as images, or review those parts separately. Logrun Lab has no OCR. Tables, columns and repeated headers or footers can affect extraction and comparison. Moved or heavily rewritten wording may appear as Added and Removed rather than a single Changed block.
Compare your own contract versions
Once you have chosen the pair and checked the text-based inputs, open PDF Compare. Put the baseline in Original PDF, the revision in New PDF, and select Compare. The limit is 20 MB and 200 pages per PDF. Password-protected or encrypted PDFs are not supported.
Document files, extracted text and comparison results are processed locally in your browser. The tool compares PDF text. It does not provide DOCX or Word tracked changes, visual comparison, or legal analysis.