Compare two PDFs and see what changed
Compare two PDFs by giving a model both files and asking what changed.
Updated
How it works
Add exactly two PDFs
Open the tool (it may ask you to sign in) and add the two files. Each one must be within the size limit.
Run Compare
The cost is shown first. The model reads the text of both files and lists the differences.
Check the changes
Open both files at the pages it names and confirm each change, especially numbers and dates.
What does Compare do?
It sends both PDFs to the model and asks it to describe how they differ: what was added, removed or reworded, and which figures changed. It's a text comparison by a model. It isn't a visual diff, and it doesn't show a tracked-changes view with red and green marks.
It suits two versions of one contract, an old and a new policy, or two quotes for the same job. It needs a paid plan, because the free plan's input cap is too small for two PDFs. See pricing for plans.
What to ask
List every difference between the two documents, grouped by section. Say which file each wording comes from.
Use the tool aboveMake a table of every amount, percentage and date that differs, with the value in file 1, the value in file 2 and the page.
Use the tool aboveCompare these two quotes: what's included in one and not the other, total price, payment terms, and anything missing.
Use the tool aboveWhich changes would affect me most? Put the three most important first and explain why.
Use the tool aboveCan I trust the list of changes?
Mostly, but not blindly. A model can miss a changed number, or report a change that isn't there. Treat its list as a map of where to look.
So check the numbers it lists. Open both files, find the amount or date, and read it yourself. Then ask a second question: "Is there any other figure that differs?" Sometimes that turns up one more.
What it will not do
- It won't mark the differences on the pages. You get a written list.
- It can't compare scans or photos. Both files need a text layer.
- It takes two files, no more, and each must be within the size limit.
- Layout and formatting changes, such as a moved logo, may not be noticed.
What does it cost, and what leaves my device?
Compare runs on Claude Sonnet 4.6 at 5 Gems per message, and both files are sent again with every follow-up.
Both PDFs are uploaded to the model provider you picked. If only some pages differ, cut them out first with the split tool, which runs on your device. To understand one version in plain words, try Explain PDF.
Questions about Compare two PDFs and see what changed
Do I need a paid plan to compare PDFs?
Yes. Compare takes two files, and the free plan's input cap is too small for that. Each message costs 5 Gems on Claude Sonnet 4.6. Check the [pricing](/pricing) page for plans.
Does it show changes like Word's tracked changes?
No. It's a written comparison by a model, not a visual diff or a tracked-changes view. You get a list of differences to check against the two files yourself.
How big can the two files be?
Each of the two PDFs must be within the limit of about 5.7 MB. If one is too large, cut the relevant pages out first with the split tool, which runs on your device.
Can it compare a scan with a new version?
Only if both have a text layer. A scan or photo has none, and there's no OCR, so you'll see "No text found". Use a digital copy of both versions.
Will it catch every changed number?
Not always. A model can miss a changed figure. Ask for a table of amounts and dates with pages, then verify each one in both files before relying on it.