Gemini vs ChatGPT (and Grok): Which AI to Use for What in 2026

The short answer: for writing and everyday tasks, start with ChatGPT. If you work in Google's apps or often need a model to look at video and audio, pick Gemini. Grok fits fast-moving topics and people who like a blunt tone. For long documents and careful code review, try Claude. For research with sources, use Perplexity, and for cheap bulk work, use DeepSeek. Don't take any ranking on faith, including this one. Run your own prompts through two or three of them before you pay for anything.

How we compared: the criteria that matter

Benchmarks change with every release, so we ranked the tools by one rule: how many of your everyday tasks one tool can cover on its own. General assistants come first, specialists later. We looked at six things:

1. Reasoning. Can it solve a multi-step problem without losing track halfway?
2. Writing. Does the text sound like a person wrote it, and does it follow your style notes?
3. Code. Is the answer correct and complete, and does it explain the tradeoffs?
4. Files and media. What can you feed it: images, PDFs, video, audio?
5. Fresh information. Does it know what happened last week, and does it show sources?
6. Cost. What one request costs compared with the value of the answer.

To see these models in practice before reading on, you can use ChatGPT online and try Gemini online in the same account.

Gemini vs ChatGPT vs Grok: comparison table

The "Inputs on Moleculs" column lists what the models accept in the Moleculs catalog as of October 2026. The vendors' own apps may differ.

ChatGPT

Who it's for: anyone who needs one assistant for drafting, editing, summarising and the odd bit of code. OpenAI's own app adds voice and image generation.

What it does well: it follows detailed instructions on tone, length and structure. On Moleculs the ChatGPT line runs from light to heavy. ChatGPT 6 Luna costs 1 credit per run, 6 Sol costs 7, 5.6 Terra costs 12, 5.5 costs 28 and 6 Astra costs 57. ChatGPT-5.5 is the only one in this line that accepts video and audio on top of images and files.

Where it's limited: cost per run varies so much between tiers that picking the wrong one by habit gets expensive. Start with a light model and move up when the answer falls short.

Skip it if most of your work is video analysis or long source documents. Gemini handles video on more tiers, and Claude is built for long inputs. If you need a starting point for prompts, there's a set of ready-made ChatGPT prompts.

Gemini

Who it's for: people who already live in Gmail, Docs and Drive, and anyone who regularly hands a model a recording, a screen capture or a long PDF. Google's own app connects to its other products, and that's often the deciding factor.

What it does well: video and audio input come with most tiers. On Moleculs, Gemini 3.1 Pro (10 credits), Gemini 4 Argon (10), Gemini 3.7 Flash (4) and Gemini 3.8 Flash (2) all accept images, video, audio and files, with up to 16 images per request. Gemini 3.1 Flash Lite costs 2 credits and takes images and files only. The full lineup is on the Gemini 3 models page.

Where it's limited: answers can be long and heavy on headings unless you set the format up front. Asking for "five bullets, no intro" usually fixes it.

Skip it if you mostly write short-form copy and care about voice more than input formats. ChatGPT or Claude may need fewer revisions for that. To get cleaner output faster, borrow some prompts that work well with Gemini.

Grok

Who it's for: people who follow news, markets or tech chatter and want an assistant that answers directly without much hedging. xAI's own app is closely tied to X.

What it does well: it's quick and conversational. On Moleculs there are three tiers, all accepting images and files. Grok 4.2 costs 3 credits and is described in the catalog as cost-efficient, with a 2M-token context window. Grok 4.6 costs 9. Grok 4.7 costs 6 and is the xAI model aimed at code, agentic tasks and long context.

Where it's limited: the directness is a style, and it doesn't fit a board memo or a legal summary without editing. The real-time features of the X-connected app may not carry over when you use the model elsewhere.

Skip it if structured long-form writing is your main output. Use Grok as a second opinion or a quick check on what's happening right now. If you're deciding between it and the default pick, our Grok vs ChatGPT comparison covers what Grok does differently.

Claude

Who it's for: people who work with long documents, contracts, research papers and large codebases, and want a careful, consistent answer more than a fast one.

What it does well: it keeps a consistent structure over long inputs and explains its reasoning on code. On Moleculs, Claude Opus 5.5 (13 credits) is listed as Anthropic's flagship for complex reasoning, code and long agentic tasks. Claude Sonnet 5 costs 16, Claude Haiku 4.5 costs 5 for lighter jobs, and Claude Fable 5.1 costs 68. Every Claude model takes images and files, up to 20 images per request, the highest limit among the text models here.

Where it's limited: none of the Claude models in the catalog accept video or audio. If your source is a recording, use Gemini.

Skip it if you need live web results with sources. That's Perplexity's job.

Perplexity

Who it's for: anyone whose question starts with "what's the current state of..." and who needs to check where every claim came from.

What it does well: it searches the web and cites its sources in the answer. On Moleculs there are three options. Perplexity Sonar costs 2 credits. Sonar PRO costs 15 and adds real-time search with image input. Sonar Deep Research costs 8 and runs longer research with cited sources.

Where it's limited: it's a research tool, not a writing partner. Drafts come out as summaries, so take the findings to ChatGPT or Claude to turn them into prose.

Skip it if your question doesn't depend on current information.

DeepSeek

Who it's for: people who run many similar requests, such as classification, extraction, quick rewrites or first-pass reasoning, and watch the cost of each one.

What it does well: it's among the cheapest reasoning-focused options here. On Moleculs, DeepSeek V4 Flash costs 1 credit and DeepSeek V4 Pro costs 2, and both accept images, video, audio and files. One ChatGPT 6 Astra run costs as much as 57 DeepSeek V4 Flash runs, so you can test an idea many times for the price of one heavy request.

Where it's limited: tone gets less polish. Expect to edit the wording.

Skip it if the final text goes straight to a client. Draft cheaply here, then polish with a stronger writer.

Moleculs: when you want all of them under one subscription

Who it's for: people who have read this far and still want to use two or three of these tools rather than pick one.

What it does: Moleculs gives you access to ChatGPT, Gemini, Grok, Claude, Perplexity, DeepSeek and others with one account and one subscription. Every request spends credits, and each model's cost per run is shown next to it, so the gap between a 1-credit and a 57-credit model is visible before you hit send. The free plan includes a quota of 5 credits, enough for a few test requests on the lightest models. For paid plans, see the pricing page.

Where it's limited:

• Moleculs doesn't build models. It gives you access to other companies' models.
• A model in Moleculs may not match the vendor's own app: settings and the features around the model can differ.
• There's no side-by-side view. You run the same prompt on each model in turn and compare the answers yourself.
• There's no mobile app. Everything runs through the interface.

Skip it if you have already settled on one vendor and use its app features every day. Its own subscription will cover that better.

How to run your own Gemini vs ChatGPT test in 15 minutes

1. Pick three real tasks (3 min). Use one reasoning problem, one piece of writing you need, and one coding task from your own codebase. Toy examples tell you nothing.
2. Write down what a good answer looks like (3 min). Define correct, complete and the right length before you see any output, so a confident tone doesn't win by default.
3. Run each prompt on two or three models (6 min). Use the same wording with no follow-ups. Start with mid-tier models, such as Gemini 3.1 Pro against ChatGPT 6 Sol, and add Grok 4.7 as a third.
4. Score and note the cost (3 min). Mark which answer you would ship as it is, then check the credits each one used.

If you don't want to write test prompts from scratch, ask a model to generate the test set for you.

Pick by situation:

• You only need text: start with ChatGPT and keep Claude for long or high-stakes documents.
• You send recordings, videos or screenshots: use Gemini.
• You follow fast-moving topics: use Grok for a quick read and Perplexity when you need sources.
• You run lots of small requests: use DeepSeek, or the light tiers of ChatGPT and Gemini.
• You're on a tight budget: start with the free plan, and see our guide to free ChatGPT, Gemini and Grok alternatives.
• You want one bill for all of them: use Moleculs, as long as you accept that some vendor-specific features won't be there.