1In one sentence
A chat is a back-and-forth where ChatGPT remembers everything said so far, and the Think button (on Free and Go) or the model picker and thinking slider (on paid plans) let you choose between a quick answer and a slower, more careful one.
2New words
- Model — the version of ChatGPT's brain. In late 2026 the main family is GPT-6: GPT-6 Luna (smaller and faster, the one Free and Go get), GPT-6 Sol (bigger, for paid plans) and GPT-6 Astra (the strongest, for hard jobs; in Chat it powers "GPT-6 Pro" on Pro). The older GPT-5.5 was removed on October 14, 2026. The names change every few months; the help pages list the current ones.
- Model picker — a menu at the top of the chat where paid plans choose the model. Free and Go do not have it; they always get the same model.
- Think — a button next to the message box on Free and Go. Press it and ChatGPT reasons for a while before answering, which helps with math, logic and tricky planning.
- Thinking level — on paid plans, a slider instead of a button, with steps such as Instant, Medium and High (Pro and Business get higher steps too). Higher means slower and more careful.
- Context — everything in the current chat. ChatGPT reads all of it before each answer, so earlier messages shape later ones.
- Intelligent UI — since October 2026, GPT-6 can put small interactive charts, buttons and calculators right inside an answer when that explains things better than text. You can turn the visuals down if you prefer plain answers.
3Why you would want it
Most questions need no thinking time; a fast answer is fine. But when you ask ChatGPT to check a budget, untangle a contradiction, or plan something with many moving parts, pressing Think (or raising the level) gives noticeably better answers. Knowing this saves you from blaming the tool when you simply used the quick setting for a hard job.
4Try it now
- In a new chat, type: I have 3 shifts to fill at a bakery on Saturday: 6-10, 10-2, 2-6. Ana cannot work before 9, Ben cannot work after 3, Cara can do anything but only one shift. Who works when?
- Read the answer.
- Start a new chat, press Think (or set the level to High), and ask the same question.
- Compare. The second one should show its reasoning and be more reliable.
5What you will see
On Free and Go, there is no model picker; the Think button sits next to the message box (it also appears as "Thinking" in the "+" menu). On a paid plan, the model picker is at the top of the chat, with the thinking slider nearby:
The model picker open
With Think on, a short "Thinking..." line appears before the answer, sometimes with the answer starting to appear while it keeps thinking. Some answers now also include a small chart or calculator you can click.
6Watch out
- Thinking uses more of your allowance and takes longer. Do not leave it on for small talk.
- A very long chat slowly "forgets" early instructions. When answers drift, start a fresh chat and put a clear brief at the top.
7Go further
Ask the same hard question with and without Think three times and note which you trust. Then read Chapter 1.6 to give ChatGPT files and photos to work on.