How do you choose between GPT-4o, o1 and o3-mini?

ChatGPT's model menu has grown crowded. A paid subscriber now sees GPT-4o, o1, o3-mini and o3-mini-high, and free users have a "Reason" button that calls on o3-mini. The names don't explain themselves, so it's worth understanding the one big split behind them.

GPT-4o is a general-purpose model: it answers quickly and handles text, images, voice and files. The "o" models are reasoning models. Before answering, they spend extra time working through the problem in a hidden chain of thought, checking and revising their steps. That makes them stronger on problems with a right answer that takes several steps to reach, and slower and more expensive on everything else. When OpenAI introduced its first reasoning models in September, it said plainly that GPT-4o would remain the better choice for many common tasks.

The three models in brief

GPT-4o is the everyday model. It's fast, conversational, works with search, uploaded files and images, and is the right default for writing, summarizing, brainstorming and questions where speed matters more than depth.

o1 is OpenAI's broad reasoning model. The full version replaced the preview in December and is available to all paid subscribers. It can reason about images you upload, which matters for diagrams, charts or a photo of a handwritten equation. OpenAI describes it as its general-knowledge reasoning model.

o3-mini, released on January 31, is a smaller, cheaper and faster reasoning model aimed at science, math and coding. In ChatGPT it thinks at a medium level of effort by default; o3-mini-high thinks longer for harder problems. It does not accept images, and OpenAI points developers to o1 for visual reasoning. It can, however, search the web, which OpenAI calls an early prototype. Plus and Team users get 150 o3-mini messages a day.

A task-by-task table

These are starting points, not rules. If GPT-4o's answer to the statistics problem is right, you've saved time; if it isn't, the reasoning model is one click away.

A quick test you can run

Paste the same problem into each model and compare time, length and correctness:

A store sells notebooks at $3 each or 4 for $10. Pens cost $1.50 each or 3 for $4. I have $27 and need at least 6 notebooks and at least 5 pens. What is the cheapest combination that meets the minimums, and what is the most notebooks I can buy if I spend all my money while still getting 5 pens? Show the arithmetic.

You'll typically see GPT-4o answer almost instantly and the reasoning models pause first, sometimes for many seconds. Check each answer's arithmetic yourself. On puzzles with several constraints, the extra thinking time often pays off; on a simple question, it's wasted waiting.

Which tasks are worth a reasoning model?

A reasoning model earns its extra time when the problem has three features: several dependent steps, a result you can check, and a real cost to getting it wrong. Math and statistics problems, code that has to run, logic puzzles, scheduling with many constraints, and comparing a document against detailed rules all fit. OpenAI's own numbers show the gap on such work: on a qualifying exam used to pick International Mathematics Olympiad teams, GPT-4o solved 13% of problems while its first reasoning model solved 83%.

Choose between the reasoning models by the kind of problem. For technical work where speed matters, o3-mini is the efficient pick; OpenAI reports that testers preferred its answers to o1-mini's and that it made fewer major errors. Raise it to o3-mini-high when the problem is hard. Reach for o1 when the problem draws on wide general knowledge or includes an image.

For most other everyday work, such as drafting, rewriting, summarizing, translating, brainstorming or chatting through an idea, GPT-4o is still the better tool. It's faster, it supports the most features, and there's no hidden puzzle for extra thinking to solve. A useful habit is to start there and switch up only when the first answer shows the problem needs more careful work.