ChatPDF

In this video we will take a look at ChatPDF and compare it with ChatGPT—both the free and the Plus version—which one you should use, and whether the free tiers are enough or you need a premium subscription. Spoiler alert: there are some significant differences to keep in mind depending on what type of PDF you want to chat with, so stay tuned.

My name is Florian Walther and this is AI Tool Corner, where I review the latest AI software to find out which ones can actually improve your life and business.

Let's start with the setup of each of them. Technically you can use ChatGPT without even creating an account; however, when I tried to upload a PDF, even a smaller one, it didn't work—I just got an error message and nothing happened. Also, if you don't create an account it uses the inferior GPT-4o mini model, which is not as good as the latest GPT-4o model. If you create an account, even a free one, you can use GPT-4o—so if you want to use ChatGPT you should create a free account via the sign-up button. Then you get access to better models, but there are also rate limits on the free tier: a certain number of messages and uploads in a given timeframe, and after that it either blocks you or downgrades to a cheaper model that doesn't perform as well. Nevertheless, the free tier of ChatGPT is quite powerful.

ChatPDF also has a free tier, and you can even use it without creating an account—you go to the website and drag and drop your PDF directly in. This uses the more powerful GPT-4o model even if you don't create an account, which is a small advantage over the free ChatGPT version—but only if you don't create an account. With a free account you can only upload up to two PDFs per day; they can't have more than 120 pages or be bigger than 20 megabytes. I already exceeded this limit, so if I try to upload another file I get a dialog that tells me I need to get a subscription. As you can see the price is €25—and I assume also $25—per month, or you can save about 60% with a yearly subscription. Prices and limits might change over time, but this is what it was at the time of making this video. On the paid plan you can send unlimited questions and upload PDFs up to 2,000 pages, which is more than enough to upload a whole book; you can actually upload multiple files and chat with them at once, so technically you can exceed 2,000 pages across files—but more on that in a moment.

ChatGPT Plus is cheaper—only about $20 a month—and they don't have a yearly subscription at the moment where you save money, but ChatGPT can do more stuff like image generation. So we want to find out whether it's worth getting ChatPDF if chatting with PDFs is your main task. Going forward I will use the paid tier of ChatPDF, and there is a link in the video description where you can create your own ChatPDF account.

Uploading a file to ChatPDF is simple: you click the upload PDF button or drag and drop your PDF. Both ChatPDF and ChatGPT support different file types—not only PDFs but also text files, Word documents, Google Docs, and even PowerPoint files. To test this I uploaded an air fryer instruction manual.

The first thing you notice on ChatPDF is the side-by-side view: the whole PDF on the left and the chat on the right. This is very useful, especially with the citation links ChatPDF provides—more on that in a moment. You also get question suggestions. What's funny is that the greeting message was in Dutch—I assume because it's a multilingual instruction manual—but if you ask a question in English it continues in English.

Uploading files to ChatGPT works similarly: you click the attachment button or drag and drop your PDF into the input field. I exceeded the upload limit with my free account, but I have another active chat where I already uploaded the file so you can see how it looks. Here I uploaded the PDF, but ChatGPT doesn't have a side-by-side view—we can't see the PDF itself, only the chat.

Let's start asking questions. I began with a very general question: I just want to cook a few burgers—how do I do it? I expect the AI to find the relevant information and give me the instructions I need. When we compare the response on ChatPDF with the responses on both free ChatGPT and ChatGPT Plus, they're pretty similar—they basically say the same things and use roughly the same structure, which makes sense because ChatPDF uses ChatGPT under the hood, so the models are the same and the instructions are aligned. It mentioned that I have to install the crisper plates—which is important—or that I should avoid having food overlapping; that's all mentioned in the manual in different places.

The difference between ChatPDF and ChatGPT is that on ChatPDF we get citation links automatically—we can click them and they bring us to the page where the AI got the information from. For example it brought me to page 16, but you can see it calculates pages wrong—I assume because those are double spreads: two pages per sheet of paper. That works correctly if you actually have one logical page per sheet. It also jumped to what looked like the French instructions—you can't really blame it because they all say the same thing in different languages—so it picked one and jumped there. ChatGPT doesn't do any of that—it doesn't give page numbers. What I tried was asking it specifically to list all the pages it used to create this information; it gave me a list of page numbers, but I tried it twice and got completely different page numbers each time, so that doesn't seem very reliable. ChatPDF is usually pretty exact—but again, only if your pages are structured properly.

Next I tried a more specific question: my food is burned—what did I do wrong? There is information about this in the manual ("why is my food burned"). I expected the AI to find this specific information and give an answer. Again the results between ChatGPT and ChatPDF are very similar—both complete and structured the same way—but again we have those useful citation links in ChatPDF, and each paragraph in the list has its own citation link.

Next I wanted to test image recognition. I asked ChatPDF where the air intake vents are placed on this unit. On the image the vents are here on the front and sides, but ChatPDF answered they're located on the back and side of the unit—plain wrong. Next I asked whether the handles on the drawers—these ones here—are vertical or horizontal, and I specifically told it to look at the images. It said it doesn't have the capability to view images in a PDF, so images here won't be recognized. I tried the same with ChatGPT; again the answers were wrong, and even when I asked it to look at the images it gave the wrong answer—it said the drawers were horizontal, but as you can see they're vertical. My guess is ChatGPT probably can't really look at images inside PDFs either, which is probably why ChatPDF doesn't advertise it—because they use ChatGPT under the hood.

Next let's look at how they handle multiple files. In ChatPDF you can create a folder and upload multiple PDFs—I uploaded three books which are very large files—and instead of clicking an individual file you click the folder, so you can chat with all three at once. On ChatGPT you drag and drop your files here too; that works, but the free tier could only take two of the three books, which is still a lot—you don't have those limits with either ChatGPT Plus or paid ChatPDF if you have a paid subscription.

First I asked it to give a brief summary of each uploaded book, which it did in both cases—but I don't know how much of that is drawn from the PDF itself versus general knowledge from the broader internet. So I tried a more specific question: what was the name of the advisor who convinced Genghis Khan not to destroy China—because this is mentioned in The 48 Laws of Power. Let's look at ChatPDF first: it gave a very concise answer and mentioned the name Yelü Chucai, with citation links. Checking whether they're correct: it brings me to the correct book out of the three—The 48 Laws of Power—and Chucai is mentioned—great. ChatGPT also gave me the answer, but I noticed Yelü Chucai is spelled differently than in the book; ChatPDF gave the exact spelling from the book, ChatGPT a different spelling. My suspicion was that ChatGPT didn't actually get this from the PDF but from general knowledge. I asked how the name is spelled in the book—it generated two different responses and neither really nailed it; the answer was also much lengthier with information I didn't care about. ChatPDF was much more specific.

Before the final summary, a few other features. ChatPDF has an AI Scholar tool to search and summarize research papers—useful for academic work. I asked whether red meat causes cancer—the research says yes; I personally think it doesn't—but let's see. On the left we have different research papers it found; on the right a summary. Pretty cool, but there's no chat—you can't ask follow-up questions; maybe they'll add that later. I'd say it's a nice-to-have, probably not essential for most people.

Security: ChatPDF says data you send is encrypted and encrypted at rest, so people at the company shouldn't be able to read your PDFs—but they use ChatGPT under the hood, so you also have to look at ChatGPT's data handling. ChatGPT uses your data for training by default but you can opt out—there are instructions on their site. However, that means they're able to read your data—it's not encrypted on ChatGPT's servers the same way—employees could see messages and uploaded files. For most people it's probably not a big deal, but you should avoid sending sensitive data like passwords, personal information, or company secrets.

Mobile usage: ChatPDF now offers native mobile apps (iOS and Android) and desktop apps (Windows and Mac) in addition to the browser. When this video was recorded I used the mobile web experience; if you prefer an installed client, use ChatPDF’s mobile or desktop downloads. ChatGPT also has a native mobile app—choose whichever fits your devices and workflow.

To summarize—which should you get: ChatPDF, ChatGPT Plus, or one of the free tiers? ChatPDF is much more precise with large amounts of text—it consistently found specific passages and provided useful citation links straight to the page. The side-by-side view is very useful because you always have the PDF in front of you. AI Scholar is a nice extra depending on your work. ChatGPT Plus has more features—you can upload images, generate images, browse the web, and they're adding features constantly.

I'd say get ChatPDF if you work with large amounts of text and need to be very exact—if you want to chat with research papers, ChatPDF is clearly stronger—or chat with a book because it finds specific locations much better than ChatGPT Plus did in these tests. If you don't need that level of exactness—if it doesn't matter which page something came from or whether it came from the internet instead of the book—you can use ChatGPT instead. I wouldn't rely on it alone for academic work the same way, but for most people who also want image generation and similar extras, ChatGPT may be enough.

Again, the link to ChatPDF is in the video description. Subscribe if you want more AI tool reviews—I hope to see you in the next video. Take care.