Grok vs ChatGPT: Which One to Use, and What Grok Does Differently

Grok vs ChatGPT: the short answer

Use Grok in xAI's own app if you want answers that draw on what people are posting on X right now, or if you like a looser, more informal tone. Use ChatGPT if you want a general assistant for writing, analysis and code. ChatGPT-5.5 also takes images, audio, video and files. If your input is a call recording or a screen capture, look at Gemini. If you work with documents, screenshots or code, try Claude as well. For plain writing and reasoning the gap between Grok and ChatGPT is small, so the fastest way to decide is to run your own task through both. The last section shows how to do that for a few credits.

How we compared them: the criteria that matter

Grok and ChatGPT come first. After them come the alternatives you'd switch to when neither fits. We compared five things:

• What it accepts. Text only, or also images, files, audio and video.
• What it produces. Text, images, video.
• Writing and code. How it behaves on a real request, not on a leaderboard.
• Tone. How much editing the output needs before you can send it.
• Cost per run. We quote credits on Moleculs as of November 2026. These are the only prices we can check ourselves, and you see the same numbers when you try Grok online. Vendor subscriptions are priced separately and change often, so check xAI's and OpenAI's own sites for those.

Comparison table: Grok, ChatGPT and the alternatives

Grok (xAI): what it does that ChatGPT can't

Who it's for: people who follow news and discussion on X, developers who want a second opinion on code, and anyone who finds ChatGPT's default tone too careful.

What it does well. xAI's own Grok app is tied into X. It can pull in live posts and trending topics, which none of the other models here do natively. The tone is looser too: Grok will joke, take a side and drop the hedging. For brainstorming or a quick gut check, that's useful.

On Moleculs you get three Grok text models:

• Grok 4.7, 6 credits per run. xAI positions it as its flagship for code, agentic tasks and long context.
• Grok 4.6, 9 credits per run.
• Grok 4.2, 3 credits per run, the lighter option when you have a lot of requests to get through.

All three accept up to 10 images and files. The flagship costs less per run than Grok 4.6, so pick 4.6 only if it does noticeably better on your task.

Where it's limited. The X integration belongs to xAI's products. In a third-party interface you get the model, not the X feed. None of the Grok text models take audio or video as input. The informal tone cuts both ways: for a client email or a policy document, ask for a formal register in the prompt.

When to skip it. Skip it if your input is a recording, or if the output has to sound formal and you don't want to keep correcting the tone.

ChatGPT (OpenAI): where it still leads

Who it's for: people who want one default assistant for writing, analysis, summaries and code.

What it does well. The main practical difference is input. ChatGPT-5.5 accepts images, video, audio and files, so you can hand it a voice memo or a short clip alongside your text. On Moleculs it's the only model from OpenAI or xAI that takes all four.

The other strength is range. You can find ChatGPT models on Moleculs from 1 credit to 57 credits per run:

• ChatGPT 6 Luna: 1 credit
• ChatGPT 6 Sol: 7 credits
• ChatGPT-5.6 Terra: 12 credits
• ChatGPT-5.5: 28 credits
• ChatGPT 6 Astra: 57 credits

All of them accept images and files. The catalog doesn't label these tiers by task, so price is your main guide. Start cheap and move up when an answer falls short.

Where it's limited. ChatGPT-5.5 costs almost five times as much per run as Grok 4.7, and Astra nearly ten times as much. If you send dozens of requests a day, that adds up. Picking a tier takes some trial and error. OpenAI's own app has features that a third-party interface doesn't copy.

When to skip it. Skip it if your question is about what's happening on X right now, or if you need high volume at the lowest cost and the cheap tiers don't hold up on your task.

Grok Imagine vs ChatGPT Image: pictures and video

Grok Imagine covers both still images and motion in one family:

• Text-to-image: 11 credits per run
• Text-to-video: 62 credits per run
• Image-to-video: 62 credits per run. You give it a photo and it animates it.

That's handy when you want a still and a short clip from one family of models. If you start with stills, here's Grok Imagine for images.

OpenAI's image models make images only, but there are more of them, and all accept up to 10 input images as references:

• GPT Image 2.5 Flare: 6 credits. Described as fast, high-quality generation for most tasks.
• GPT Image 2.5 Sunburst: 6 credits. Described as maximum quality and precise edits of complex images.
• ChatGPT 5 Image Mini: 8 credits. A faster, cheaper GPT Image model.
• ChatGPT Image 2: 15 credits.

How to choose. If you need video, or a still you'll animate later, start with Grok Imagine. If you're editing an existing image with several references, such as a product shot, a layout or a brand asset, start with Sunburst. A Grok Imagine video costs about six times as much as an image, so get the still right first.

Gemini: when you need audio and video input

Who it's for: people whose input isn't text: meeting recordings, lectures, podcasts and screen captures of a bug.

What it does well. Four Gemini models on Moleculs accept audio, video, images and files:

• Gemini 3.8 Flash: 2 credits
• Gemini 3.7 Flash: 4 credits
• Gemini 3.1 Pro: 10 credits. Described as Google's flagship for high-precision multimodal reasoning.
• Gemini 4 Argon: 10 credits

They take up to 16 images per request. ChatGPT-5.5 also accepts audio and video, but at 28 credits. For "summarise this recording" or "what goes wrong at 0:40 in this clip," Gemini is the cheaper first try.

Where it's limited. Gemini 3.1 Flash Lite (2 credits) takes only images and files, so check the model before you upload a recording. Gemini has no X integration, and Google's own app has features that a third-party interface doesn't copy.

When to skip it. Skip it if everything you send is text. Then the choice comes down to tone and cost, and Grok or ChatGPT is a simpler place to start. For a closer look at that pairing, see our Gemini vs ChatGPT breakdown.

Claude: for documents, screenshots and code

Who it's for: people who send documents, scans or screenshots to a model, and developers who want another opinion on code.

What it does well. Anthropic positions Claude Opus 5.5 (13 credits) as its flagship for complex reasoning, code and long agentic tasks. The rest of the lineup on Moleculs:

• Claude Haiku 4.5: 5 credits, for quick tasks
• Claude Sonnet 5: 16 credits
• Claude Fable 5.1: 68 credits, the most expensive text model in this comparison

Claude models accept up to 20 images per request, more than any other model here, plus files. That helps when you're sending a stack of scanned pages or screenshots.

Where it's limited. Claude takes no audio or video and doesn't generate images. Fable 5.1 costs more than five times as much as Opus 5.5, so try Opus first.

When to skip it. Skip it if your input is a recording, or if you want something visual as the result.

Moleculs: Grok and ChatGPT under one subscription

Who it's for: people who want to test Grok and ChatGPT on real work before paying for either vendor's subscription, and people who use text, image and video models and want one bill.

What it does. Moleculs gives you access to models from xAI, OpenAI, Google, Anthropic and others through one interface. Every model in this article is in one catalog, and each model's cost per run is shown next to it. Your plan includes a credit quota that renews every paid period. For plan details, see the pricing page.

Where it's limited.

• Moleculs doesn't build models. It gives you access to other companies' models.
• A model here may not behave exactly like it does in the vendor's app. Settings and the surrounding features can differ.
• Features built around X, like reading live posts, stay in xAI's own products.
• There's no window that shows two models' answers side by side. You run the same prompt in each one.
• There's no mobile app.

When to skip it. Skip it if you rely on one vendor's app-specific features every day and never use other models. In that case, a direct subscription is simpler.

How to test Grok and ChatGPT on your own task

Benchmarks tell you how a model does on someone else's problem. This test takes about ten minutes:

1. Pick a real task. Use something you need this week: a reply to a tricky email, a bug with its stack trace, a summary of a document you've already read. Skip riddles.
2. Write the prompt once. Paste the exact same text into each model. If you tweak it between runs, you're testing your prompts, not the models.
3. Start cheap. A guest can send one request without signing up. The free plan comes with 5 credits, enough for Grok 4.2 (3 credits) and ChatGPT 6 Luna (1 credit) on the same prompt. To compare the flagships, Grok 4.7 at 6 credits and ChatGPT-5.5 at 28, you'll need a paid plan.
4. Judge on three things. Did it follow every constraint, including length and format? Do the facts hold up when you check two of them? Would you send it without editing?
5. Run it twice. One good answer can be luck. Two in a row is a pattern.

If you don't have a task handy, send the four-day work week prompt. It asks for three arguments each way, examples, a word limit, and the point the model is least sure about, so you can see how each model handles uncertainty. For more starting points, browse ready-made Grok prompts and run the same ones in ChatGPT.

Pick by situation

• You want what X is talking about right now: Grok in xAI's own app.
• You only need text and send a lot of it: Grok 4.2 or ChatGPT 6 Luna. Test both and keep the cheaper one that holds up.
• You're working on code: Grok 4.7 and Claude Opus 5.5 on the same bug. Compare the diffs.
• Your input is a recording or video: a Gemini Flash model first, ChatGPT-5.5 if you need a second opinion.
• You need a picture and a clip from one family: Grok Imagine.
• You're editing an existing image with references: GPT Image 2.5 Sunburst.
• You want all of the above on one bill: Moleculs, as long as you can live with the limits listed above.