Find what changed between two drafts of a document

See what changed in four steps

You need both drafts as PDF files. After that, the tool does the reading for you, and you only look at what changed.

1. Save each draft as a PDF, if it isn't one already. The next section shows how.
2. Open Compare PDF in your browser. Put the older draft under Original and the newer one under Changed version.
3. Read the summary. It says how many changes were found, split into added, removed and changed, or it says "No differences in the text".
4. Go through the changes one by one. Use the arrows in the toolbar (or the N and P keys on a keyboard), or switch to List to read every change as a card, with the words before and after.

Every button is explained in the tool's step-by-step guide. This article is about what the guide can't cover: working with drafts. Which two to pick, what edits look like, how to check someone's changes, and what a comparison cannot see.

First, get both drafts as PDFs

Compare PDF reads PDF files only. Drafts usually live in Word or Google Docs, so save a copy of each one as a PDF, both in the same way.

• In Word, save a copy as a PDF. Look for PDF in the Save As or Export choices.
• In Google Docs, use the File menu to download the document as a PDF.
• No Word on your phone? Word to PDF turns a DOCX file into a PDF in your browser, with nothing uploaded. It reads DOCX files, not the older .doc ones.

Before you save

• Show the final text. If a draft has tracked changes on it (coloured insertions, struck-out words, comment balloons), switch to the view that shows the final text without markup before you save. Otherwise the markup can end up in the PDF, and any of it saved as text would be compared as words.
• Use the same program for both. A PDF made by another program can store its text in a different order, for example in two columns, and that makes extra changes.
• Check that it has real text. A PDF saved from Word or Google Docs has its words inside. A scan is only a picture of the page, and the tool tells you when a file has no text.
• Name the files clearly, like thesis-draft-1.pdf and thesis-draft-2.pdf.

If your drafts are photos or scans of pages, there are no words to compare, but the tool can compare how the pages look: see scanned PDFs. JPG to PDF turns photos into one PDF first.

Which two drafts should you compare?

The two files you pick decide which question you answer:

Put the older file under Original. Then "added" means new in the latest draft. If you choose both files at once in the file picker, the tool puts the older one first, going by the date each file was last changed on your device. That date may not be the day the draft was written (a file you downloaded or received may show a later date), so check the order. If new text shows as removed, press the swap button between the files and the changes are found again the other way.

Comparing round by round (draft 1 with 2, then 2 with 3) gives short lists that are easy to check. Comparing the first draft with the latest shows the total distance, but it hides anything added in one round and taken out in the next, because that text is in neither file.

What different edits look like

Green with a line under it is added, red with a line through it is removed, and yellow with a dashed border is changed. This is how the common edits to a draft show up:

That last row matters. The words are compared as one long line, not page by page, so a document that grew, or was laid out again, doesn't fill the list. In our test, the same 21 pages of text laid out again on Letter paper with other margins, so they became 20 pages, gave "No differences in the text". That is with Ignore extra spaces and line breaks on, which is how it starts. Turn it off only when the lines themselves matter, as in a poem. See the two options.

Did someone change every heading to Title Case? Turn on Ignore capitals and the files are compared again straight away. Switch it off for a last check, because a capital can matter in a name or a code.

A worked example: a 3-page assignment

This is an example, not a test result. Say you send a 3-page assignment to your teacher on Monday. On Thursday it comes back as a PDF with nothing marked. You put Monday's PDF under Original and Thursday's under Changed version. The summary says 6 changes: 2 added, 1 removed, 3 changed. You step through them:

1. Page 1, changed: the heading "Introduction" became "Background". Harmless, unless the text later says "as stated in the Introduction".
2. Page 1, added: a new sentence that explains a technical term. It isn't your wording, so decide whether to keep it or say it your way.
3. Page 2, changed: "increased by 12 percent" became "increased by 21 percent". Stop here and check your data. Either your teacher fixed your slip, or a new slip crept in.
4. Page 2, removed: a sentence with no source behind it. Most likely a cut you were asked for.
5. Page 3, changed: "affect" became "effect". A spelling fix. Accept.
6. Page 3, added: one more book in your list of references. Check that it is real and that you use it.

After one short read you know where to look: one number to check, one new sentence to read, and four small edits to glance at. Without the comparison you could read three pages twice and still miss the 12 and the 21.

When someone edits your file and marks nothing

A teacher returns your report with "corrected" on it. A manager tidies your proposal. A co-author forgets to turn on Track Changes. You have a new file and no idea what is different. Compare their copy with yours, in a way that keeps you in control:

1. Keep your own draft as it was. Before you send a draft out, save a copy named like proposal-sent.pdf, and never overwrite it.
2. Put yours under Original and theirs under Changed version, so "added" means "they added it".
3. Read every change before you accept any. Give the red ones extra care. Removed text is easy to miss, because there is nothing new to read.
4. Sort the changes into three piles: fine as it is, needs a question, needs undoing. The List view suits this, because the words before and after are on each card.
5. Make your decisions in your own file. Compare PDF shows the changes, but it can't accept, undo or merge them, and it can't edit a PDF. You do that part in Word or Google Docs.
6. Ask about anything you don't understand. Copy list or Save report gives you every change as plain text, with its number, its page and the words before and after, ready to paste into a message.

If you both work in Word, its Track Changes and Compare features let you accept or reject edits one by one, and in Google Docs the version history may already show who changed what. Compare PDF is for when all you have are two PDFs, or you are on a phone.

Check that your corrections went in

Students, job seekers and authors often get a list to fix: "add a conclusion", "correct the dates", "remove the second table". Before you send the file again, compare it with the old one and tick the list off against the changes:

• Every correction should have a change. If one doesn't, it wasn't made. The exception is a formatting request, like "make the headings bold", which the word comparison can't see. Compare the look can, when it shows on the page.
• Look for changes you didn't mean to make. A paragraph pasted twice shows as added. A sentence lost while fixing another shows as removed.
• Check each number again. Amounts, dates and percentages are where small slips do the most harm.

Proofs and final copies

The same idea works when a printer or designer turns your approved text into a proof. Put the approved text under Original and the proof under Changed version. "No differences in the text" means the words and their order match, with the options you chose. It says nothing about pictures, colours or layout, so run Compare the look as well if those matter.

Long drafts, reports and theses

Comparing by eye fails first on long documents. In our tests, two 298-page PDFs with 6 known changes gave all 6, in 4.6 seconds in the middle of five runs. That ran in Chromium 141 (the open-source browser Chrome is built on) on a Linux computer with 4 processor cores and 16 GB of memory. A phone will usually take longer.

• You don't need to split the file. Pages and chapters don't matter, only the words and their order.
• Work from the List and the report. The List shows the first 1,000 changes, and Save report always has all of them. In the List, a very long added or removed passage shows its first and last words and a count of its words. Tap its card to see all of it on the pages.
• Note where you stopped. Every change has a number, on its card and in the report. Write down the last one you checked, and carry on tomorrow from the next.
• Expect the contents page and the index to show changes if your pages shifted, because their page numbers are read as words. They are quick to check.

List far too long? Check that both files are versions of the same document. If fewer than 35% of the words match, the summary says the PDFs have little text in common. Then check that Ignore extra spaces and line breaks is on, and that both drafts were saved as PDFs by the same program.

What a comparison of drafts can't tell you

• It shows the difference between two files, not the history. It doesn't know who made a change or when. A sentence added in draft 2 and removed in draft 3 won't show when you compare draft 1 with draft 3.
• Formatting. Bold, italics, fonts, sizes, colours and heading styles are not compared, only the words. Compare the look shows changes like these when they can be seen on the page.
• Pictures have no words. A chart pasted in as a picture won't show in the word comparison, even if its figures changed. Use Compare the look.
• Comments in the margin, and text typed into form boxes, are kept apart from the page text and aren't seen.
• Whether a change is good. The tool doesn't check spelling, grammar, facts or sources, and it is not a plagiarism (copying) check. It only shows what is different.

The full list is in what it can't see.

Habits that make the next comparison easy

• Save a new file for every round, like essay-v1.pdf and essay-v2.pdf. Never overwrite what you sent or received.
• Keep the report with the draft. Save report gives a text file whose name starts with "changes-" and then the names of the two files. It also notes which options were used.
• Compare once more before the last send. Put the file you are about to submit against the last one you checked. It catches the late slip.

Why it matters that nothing is uploaded

Drafts are often not ready to be public: a thesis before it is submitted, a bid before its deadline, a resume with your phone number. Most online PDF tools upload your files to their servers, so a copy sits for a while on a computer you don't control.

Compare PDF reads and compares both files inside your browser. They never leave your device, so there is no copy on anyone's server. You can check this: once the page has loaded, switch off Wi-Fi and mobile data and compare two files. It still works for most PDFs. Our privacy policy has the details.

Questions people ask next

Can I compare a Word file with a PDF?

Only PDFs can be compared here. Save the Word file as a PDF first, then compare the two PDFs.

My draft has tracked changes. Do I still need this?

Tracked changes show what the person chose to track. Comparing the final PDFs shows every word that differs, including edits made while tracking was off. It is a good last check.

Can it combine two people's edits into one file?

No. It shows the changes and lets you save the list, but it doesn't edit, accept or merge anything. Make the final file in your word processor.

Does it work with drafts in Hindi or other languages?

Yes, word by word, with Hindi and other scripts compared with their vowel signs. PDFs typed with older Hindi fonts store their letters in a code of their own, so use the Pages view or Compare the look for those.

Can I do this on my phone?

Yes. On a phone you see one version at a time, with a switch between Original and Changed, and the List view works well on small screens.