My supplier sent a revised contract PDF; how do I find what changed from the old version?

Why reading side by side is not enough

A single changed figure, such as payment terms going from 30 to 45 days or a late penalty from 2% to 1%, is easy to miss in a ten page contract. The eye reads what it expects, especially in text it has read before. An automated comparison does not tire and does not expect anything; it marks every character that moved.

The steps

1. Open the PDF text extractor, choose the old version, pick One combined text, extract and copy all the text.
2. Paste it into the first box of Text comparison.
3. Go back to the extractor, choose the new version with the same setting, extract and copy.
4. Paste it into the second box and press Compare.

Use combined mode for both, because Page by page adds page headings. If the supplier added a paragraph on page 3, every page break after it shifts, and the headings would show up as meaningless differences.

An example: three clauses, two versions

When phantom differences pile up

• If the supplier changed the font or the page margins, lines may break in different places, and nearly every line looks changed. Switch the comparison level to Words, and only the changed words inside paragraphs stand out.
• Arabic in some files comes out in visual order or with letters broken apart. Since both versions usually come from the same program, that repeats in both, but read any changed Arabic line against the original PDF before acting on it.
• If a page is scanned in either version, it has no text. The summary line gives it away: 9 of 10 in one version means a page never made it into the comparison.

The comparison shows what changed in the wording; it does not tell you what the change means legally. Key clauses such as liability, termination and payment deserve a full read by a qualified person when the amounts are large.