Can ChatGPT compare two versions of a document?

Yes. Paste both, label them A (older) and B (newer), and ask for a table with a row per change and columns for what each version says. It handles changed numbers well; check it yourself for sentences that were removed.

How do I check an AI comparison?

Check the rows it gave against the two documents — quick, since each row points at a section. Then read the newer document once looking only for things the table did not mention. Missing rows are the real risk.

Can I compare two PDFs by uploading both?

On most vendors, yes, and paid plans allow more and larger files per chat. For short documents, pasting the text of both into one message is simpler and works on every free plan.

Compare two documents and find what changed — AI With PDFs

Reading two versions of a document side by side to find what changed is tedious, error-prone, and exactly the kind of matching a model does well. The trick is labelling: call them Document A and Document B, say which is older, and ask for a table with a row per change. The table is what makes it checkable.

Try it

What changed between March and September?

Compare Document A (older) with Document B (newer). List every change in a table with columns: Section, Document A says, Document B says. Include anything removed or added. Do not list things that are the same in both. Use only what the two documents say.

Document A:
Riverside Community Hall — Hire Terms (revised March 2026)

1. Bookings. The hall may be booked by residents and local groups for private and community events. A booking is confirmed only once the deposit has been received. A booking made fewer than 14 days before the event requires full payment at the time of booking.

2. Fees. The standard rate is $45 per hour for residents and $70 per hour for non-residents, with a minimum booking of three hours. Registered charities and school groups pay the resident rate. The kitchen may be hired for an additional flat fee of $60 per event.

3. Deposit. A refundable deposit of $200 is required for all bookings. The deposit is returned within ten working days after the event, provided the hall has been left clean, no damage has occurred and the keys have been returned.

4. Cancellation. Bookings cancelled more than 28 days before the event receive a full refund of any hire fees paid. Cancellations between 7 and 28 days before the event receive a 50 percent refund. Cancellations fewer than 7 days before the event receive no refund. The deposit is always returned in full on cancellation.

5. Hours and noise. Events must finish by 11 pm on Friday and Saturday and by 10 pm on other days. Amplified music must stop 30 minutes before the finish time. Hirers are responsible for the conduct of their guests.

6. Capacity. The main hall holds a maximum of 120 people standing or 80 seated. The committee room holds 20. These limits are set by the fire service and cannot be exceeded.

7. Cleaning and keys. Hirers must remove all rubbish, sweep the floors and wipe the kitchen surfaces. Keys are collected from the caretaker on the day of the event and must be returned by 10 am the following morning. A lost-key fee of $90 applies.

8. Contact. Booking enquiries: bookings@riversidehall.example. Caretaker: 0400 000 000, weekdays 9 am to 5 pm.

Document B:
Riverside Community Hall — Hire Terms (revised September 2026)

1. Bookings. The hall may be booked by residents and local groups. A booking is confirmed only once the deposit has been received. A booking made fewer than 21 days before the event requires full payment at the time of booking.

2. Fees. The standard rate is $50 per hour for residents and $75 per hour for non-residents, with a minimum booking of three hours. Registered charities and school groups pay the resident rate. The kitchen may be hired for an additional flat fee of $60 per event.

3. Deposit. A refundable deposit of $250 is required for all bookings, returned within ten working days after the event provided the hall is clean, undamaged and the keys have been returned.

4. Cancellation. Bookings cancelled more than 28 days before the event receive a full refund. Cancellations between 14 and 28 days before receive a 50 percent refund. Cancellations fewer than 14 days before receive no refund. The deposit is always returned in full on cancellation.

5. Hours and noise. Events must finish by 10.30 pm on Friday and Saturday and by 10 pm on other days. Amplified music must stop 30 minutes before the finish time.

6. Capacity. The main hall holds 120 standing or 80 seated. The committee room holds 20.

7. Cleaning and keys. Hirers must remove all rubbish, sweep the floors and wipe the kitchen surfaces. Keys must be returned by 10 am the following morning. A lost-key fee of $120 applies.

Three free runs a day on the site key. Add your own key for unlimited runs.

Did it work? Compare against the list below. The two most-missed changes are the ones that are *removals* — the contact section and the sentence making hirers responsible for their guests. A model that only reports changed numbers has done half the job.
If it missed a removal: add *"Pay particular attention to sentences in A that do not appear in B."* Models are better at spotting a number that changed than a sentence that vanished.

Every change between the two versions. Use this to grade the model's table — and notice how easy it would be to miss the last two by eye.
Section	March 2026 (A)	September 2026 (B)
1. Bookings	Full payment if booked under 14 days out	Full payment if booked under 21 days out
2. Fees	$45 residents / $70 non-residents per hour	$50 / $75 per hour
3. Deposit	$200	$250
4. Cancellation	50% refund at 7–28 days; nothing under 7 days	50% refund at 14–28 days; nothing under 14 days
5. Hours	Fri/Sat finish 11 pm; hirers responsible for guests	Fri/Sat finish 10.30 pm; guest-conduct sentence removed
7. Keys	Lost-key fee $90	Lost-key fee $120
8. Contact	Email and caretaker phone number	Section removed

Knowledge check

The model's comparison lists six changes and says "all other sections are unchanged". You notice section 8 exists in A but not in B. What does this tell you?

Compare two documents and find what changed

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