The reassuring bit first: any one of the big three is genuinely good enough for almost everything you will do, so you can pick one and stop. For most people the easy choice is whichever is already inside the app you use, and all three have a real free tier, so testing costs nothing. When you want to get more out of them, they do lean different ways, and the table below shows who wins which job.
Pick by the job in front of you
| What you are doing | Reach for | Why |
|---|---|---|
| A quick question or explainer | ChatGPT or Gemini | Fast, casual, and both search the live web so the answer is current. |
| Rewrite or polish an email | Any of them | All three are fine here. Use whichever you already have open. |
| Turn messy notes into one clean piece | Claude | My pick for long, natural writing and holding a thread across a long draft. |
| Work through a long PDF or report | Claude | It handles long documents well and lays out its reasoning clearly. |
| Get help with code | Claude or ChatGPT | My picks are Claude and ChatGPT. Which one wins is the thing even experts argue about, so try both. |
| Research with today's web | Gemini or ChatGPT | Both search live and cite sources. Gemini leans on Google's own results. |
| Working inside Gmail, Docs and more | Gemini | You can switch Gemini on to try inside these apps, though it is not on automatically and the fuller version needs a paid Google AI plan. |
| Talk to it hands-free | ChatGPT, Gemini or Claude | All three have voice conversation in their apps. |
| Make an image | ChatGPT or Gemini | Both generate images and which looks best moves around, so try both. Claude does not make images. |
| Build something you reuse often | Claude or ChatGPT | Both offer Projects that save instructions and files to reuse. On Claude that needs a paid plan. |
The three, in a line each
ChatGPT
The all-rounder most people meet first. Great for quick questions, brainstorming and back-and-forth, with free web search, voice, image and file uploads, and ChatGPT Projects to keep work you come back to in one place. If you want one tool that does a bit of everything, this is the safe default. Its heavier research and agent tools sit behind the paid plan.
Claude
The writing and thinking workhorse. Reach for it when you want long, natural prose, careful reasoning, or help working through a long document, and its free tier includes web search and artifacts, which are live documents and small apps it builds beside the chat. One thing to know: it does not make images.
Gemini
Google's own AI, and the natural pick if you live in the Google world. Its free tier is generous for everyday chat, voice and images. You can also switch Gemini on to try inside Gmail, Docs and more, though it is not on automatically and the fuller version needs a paid Google AI plan. Best when your question is about Google, or when you want a capable free assistant without signing up for anything new.
The others worth knowing
The big three cover most of what a beginner needs, but two more names come up so often they are worth a line each, and each owns a clear lane.
Perplexity
An answer engine more than a chatbot. Ask it something and it replies with a short, sourced answer and clickable citations, so it is the one to reach for when you want research you can actually check: fact-finding, current events with receipts, anything where you need to trust where the answer came from. Try it at perplexity.ai.
Grok
Made by xAI and wired into X, formerly Twitter, so its edge is what is happening right now. Reach for it when you want live news, trends, or the public reaction to something as it unfolds. Try it at grok.com.
One more for a specific job: to make sense of your own stack of documents, Google's NotebookLM answers only from the sources you give it, which keeps it grounded in your own material.
The test that beats any comparison
Reviews go stale fast because the three leapfrog each other every few months. The reliable way to choose is to try them on your own work. Paste the same real task into two of them and compare the answers. This prompt makes that fair: each AI does the job, scores itself against the same marks, and owns up to where it fell short.
You are a candidate I am testing. I am deciding which AI to rely on for this kind of work, and I am giving the same task to you and to a rival, then keeping the one that does it better. So do your real best and be straight about your limits, because overselling now just loses you the job later. THE TASK (fill this in once) - What I want done: [paste the real task, for example the email to rewrite, the messy notes to turn into a post, the PDF to summarise, the question to answer]. - What a good result looks like to me: [one line, for example "ready to send", "plain English", "under 200 words", "with sources I can click"]. - Anything you should know: [the audience, the tone, and any facts or files I am pasting below]. DO THE JOB - Turn web search on if the task needs anything current, and use real sources. - Give me the finished thing in a form I can use as it stands, rather than a description of how you would do it. - If you had to assume or guess anything, mark it clearly instead of hiding it. THEN SCORE YOURSELF, so I can compare you against the other AI like for like. Rate yourself 1 to 5 on each, with one honest line of why: - Accuracy: did you get the facts right and avoid making anything up. - Usefulness: could I actually use this as it stands. - Fit: does it match the tone, length and format I asked for. - Confidence: how sure are you, and what should I double-check. THEN BE HONEST - Name the one thing you did best on this task. - Name where you struggled or fell short. - Tell me if a different kind of tool would suit this job better, and which one. Do not oversell. I would rather know your weak spots now than find them later.
Run it through two of the three on a task you actually have this week. The winner for that kind of job is the one whose answer you would happily send or use as is. This idea comes from marketing writer Rachel Moore, who runs the same prompt across all three and lets the results, not the hype, decide.
The honest catch
Once you are comfortable, do not marry one tool. The lead changes hands constantly, and the version you tried six months ago is not the one running today. Keep two you like, use each for what it is best at, and re-test now and then on a real job. And whichever you pick, still check anything that matters, because all three sound just as confident when they are wrong. If that worries you, learn to catch made-up AI answers.
Try it now
Take the next real task on your plate, a message to write, a document to make sense of, a question you have been putting off, and run it through two of the three with the prompt above. In ten minutes you will know which one suits that kind of work, which is worth far more than any league table. Brand new to one of them? Start with your first hour with Claude or getting started with ChatGPT.
A few quick questions
Which AI is best overall?
There is no single winner, and they trade the lead every few months. For most people the best one is whichever app you already use. Beyond that, pick by the task: ChatGPT or Gemini for quick questions and live web, Claude for long writing and working through documents, and Gemini for anything to do with Google.
Are they really free?
Yes, all three have a real free tier. Claude free includes web search and artifacts. ChatGPT and Gemini free both handle everyday chat, uploads and voice. Paid plans mainly add more usage and heavier tools, so trying two on the same task costs nothing.
Do I have to pick just one?
No. Plenty of people keep two open and use each for what it does best. The quickest way to find your own favourite is to run the same real task through two of them this week and keep the one whose answer you prefer.