Claude vs ChatGPT
Claude and ChatGPT share the same core concepts but use different names, this lesson maps them side by side, including gaps where one has no equivalent.
Same ideas, different words
If you have used ChatGPT and are now setting up Claude, or if you use both, the feature names can be disorienting. The underlying ideas are often the same: persistent instructions, a workspace with files, a way to shape the AI's voice. The names and locations differ.
This lesson maps the key concepts side by side. Where the mapping is clean, we say so. Where it is imperfect, a feature that exists in one app but has no real equivalent in the other, we flag that honestly rather than pretending the apps are identical.
Both products are evolving quickly. Some of the gaps below may close; some new ones may open. We hedge on anything that is likely to have changed since this was written.
| Concept | In ChatGPT | In Claude App |
|---|---|---|
| Always-on instructions | Custom Instructions, set in Settings, applied to all your chats | Profile preferences (Settings), set once, applied across all your chats; closest scope match to Custom Instructions, though less structured. Projects add a separate per-workspace instruction layer on top. |
| Workspace with files | Projects, a named workspace with its own files and memory | Claude Projects, a named workspace with its own instructions and files |
| Shareable AI assistant | Custom GPT, build one and optionally share it publicly or with your team | No direct equivalent as of mid-2026, Projects are private per-user |
| Voice and style control | Tone guidance added inside Custom Instructions | Styles, a switchable global setting that shapes how Claude writes across all chats |
Where does it live?
Claude and ChatGPT share a lot of the same ideas under different names. Pick a concept below to see which app it lives in, and whether the mapping is clean or has a gap.
Pick a concept above to compare it across both apps.
Quick translations, flip each card to see what it maps to in the other app, with honest caveats.
Question 1 of 4
You use ChatGPT and want instructions applied to every chat you start. Where do you set this?