How to Choose Between ChatGPT, Gemini, and Perplexity's Deep Research Tools

You might be used to AI chatbots answering your questions with a few sentences or even paragraphs, but how about multipage reports? With Deep Research, that's exactly what the likes of ChatGPT, Gemini, and Perplexity are doing, utilizing their large language models alongside web searches and reasoning capabilities to become research assistants of sorts.

A Deep Research query takes time (anything between five minutes to 30 minutes, depending on what you ask), but comes back to you with a detailed report on any subject you can ask about, including complex things like niche market research or scientific mysteries. Even better, all three major Deep Research AI providers now have free tiers.

Though, let's be honest, most of us aren't performing scientific research on a day to day basis. So, how can these Deep Research tools help you?

How Deep Research works

Deep Research combines the power of the open web, large language models, and new reasoning models. When you type in your prompt, it will first use a reasoning model to figure out what you're really asking. At this point, the AI chatbot might even come back to you with clarifying questions and prepare a research plan all on its own. You are free to reply with answers and edit the research plan, but this is usually optional.

Once the research begins, you can follow along with what the AI is up to using a sidebar (or separate tab, if you're using Perplexity). Here, you can see the searches the AI is making, documents it's scanning, and information it's collating.

As I mentioned above, detailed reports take up to 30 minutes, but that's only true if you're asking something really complicated. In my testing, I found that all three tools generate results in 5-10 minutes, spinning out reports that are still detailed and a couple of pages long.

When should you use Deep Research?

The best way to use Deep Research tools is when you can't find something on Google yourself, or you don't want to spend the time going through five different articles to distill the basics about a topic.

I've personally used these Deep Research tools to find a spare part code for my car that Google just wouldn't tell me. I've also used them to research a company's share price outlook, and to learn new things about the handpan, a musical instrument I can't stop obsessing over.

If you want quick answers, a regular Search in a AI chatbot is, of course, going to be better. And if you're working on a client pitch and you need a market research for five different competitors, you might want to spring for the paid version of whatever Deep Research tool you're using. But for anything in between, it's worth knowing how to use their lightweight alternatives.

How to use Deep Research tools in ChatGPT, Gemini, and Perplexity

All three competing major AI chatbots have their own Deep Research tools that work in roughly the same fashion. I'll go into detail below, but in general, you start with a prompt, as detailed as you can make it, click the Deep Research button below the prompt, and then send out your query. You can also upload documents, spreadsheets, and images as added context.

Credit: Khamosh Pathak

The limits of free Deep Research

Credit: Khamosh Pathak

The free versions of Deep Research tools are limited. Perplexity and Gemini provide the same quality of Deep Research reports to free users as they do paid plans, but they limit the usage. Perplexity is the most generous, though, with a daily limit system. Perplexity doesn't specify its limits exactly, but it will show you how many Deep Research queries you have left in a day. In my testing, I've been able to make three Deep Research queries per day. You can upgrade to the $20 per month plan to remove all limits.

Gemini limits free users to 5 searches a month, and Gemini Advanced users can generate up to 20 reports a month on the $20 per month plan.

ChatGPT has the most complex structure. Free users get access to five monthly searches using ChatGPT's lightweight model, which doesn't generate full-length reports. Still, in my experience, this free model is enough for regular day-to-day searches.

ChatGPT's $20/month Plus plan increases the limits to 10 queries a month using the full-fledged Deep Research model and 15 using the lightweight one.

How I tested ChatGPT, Gemini and Perplexity's Deep Research tools

I tested the Deep Research features on all three platforms using the same three prompts. The first was to create a beginner-friendly guide on learning the handpan, the second was to research a company's stock outlook in the market, and the third was to find a part number for a spare wheel screw cover for my car. The last one was something that I just couldn't figure out myself using Google.

ChatGPT Deep Research: To the point and robust

I found ChatGPT's Deep Research to be the most direct and robust. The reports that ChatGPT generates are easy to read, and importantly, contain the information you asked for and nothing else. ChatGPT always asks follow up questions whenever you make a Deep Research query. This can feel tiresome (it did for me), but it clearly works, and you can tell ChatGPT to proceed without follow up answers from you, if you want.

Credit: Khamosh Pathak

I saw this in both the report for the handpan and the stock research. However, ChatGPT is perhaps not the best at finding shopping links yet. While it did find me the right car part and highlighted it right at the top, it failed to find a link for buying the part in India, where I'm based (but it did find sellers in the US and Europe).

Credit: Khamosh Pathak

Gemini Deep Research: Contextual, but wordy

When it comes to Deep Research, Gemini has two strengths: The ability to edit planned research, and access to other Google products.

When you give Gemini a Deep Research prompt, it first goes out and creates a research plan. It will then show you a glimpse of this plan, and you can then edit it if you need to (just approve it if you don't need to make any edits). Unlike ChatGPT, Gemini doesn't ask you clarifying questions, instead focusing on using its integrations with your Google account for wide-level thinking. This being Google, it will include researching relevant information from around your hometown, for instance.

Credit: Khamosh Pathak

Gemini's Deep Research feature integrates with Google Search, too. Basically, when you use Deep Research, you're essentially asking the AI to perform multiple Google Searches for you. It can even take into account your browsing history (though, only if you want it to).

Credit: Khamosh Pathak

But Gemini's downside is that it's a bit too wordy, and its default research plan is often too broad in scope. It might be best to edit a research plan to make it more specific. I saw this in my test about finding a a number for my car part, where it spent multiple paragraphs talking about spare wheel covers instead of directly pointing out the part number I asked for (something that both ChatGPT and Perplexity do better). The upside is that Gemini integrates Deep Research directly into its Audio Overviews feature, though, so you can easily generate a short podcast episode based on your report.

Perplexity: Fast and made for web search

Perplexity's Deep Research tool is fast. It's the fastest at coming back with a Deep Research report, sometimes giving me answers in just two minutes or so. It does quite well with shopping links, and shopping research. And it's a one-click affair. Perplexity doesn't ask any follow up questions, nor does it ask you to approve its research plan like Gemini does. It just goes and does its thing.

Credit: Khamosh Pathak

Currently, Perplexity is adept at integrating web searches into its research, perhaps even better than Gemini is. But its speed comes at a cost. In my testing, I found Perplexity's Deep Research reports to be lacking in detail, even though there were a lot of sources attached to the report.

Credit: Khamosh Pathak

Which Deep Research tool is right for you?

All three free Deep Research tools have their uses, but some are better suited to certain tasks than others. Based on my research and testing, this is what I've found:

• ChatGPT's Deep Research documents are the most robust while staying concise, although they suffer a bit when it comes to finding specific links online.

• Gemini's Deep Research reports are the most detail-oriented, although they tend to be too verbose, and sometimes unnecessarily long.

• Perplexity's Deep Research tool is the fastest, giving me results in mere minutes. While the research it generates is not often factually wrong, it is lacking in detail or depth when compared to ChatGPT or Gemini.

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