What is the same
Both are hosted chat UIs from OpenAI and Anthropic. Both are fine for learning prompting. Both can hallucinate. Keep passwords, unpublished research, and other people’s private data out of either.
Practical differences
Tutorial gravity: More English walkthroughs still say “open ChatGPT,” which can reduce friction if you are following common tutorials.
Long notes and checklists: Claude.ai often feels stronger when you drop in long readings or “follow this list” asks.
Features and plans: Free and paid tiers, file uploads, and project folders change. Check the current product pages for limits.
Try the same three prompts
A: explain a concept you know.
B: make a seven-day plan with real constraints (hours, weak spots).
C: critique your own outline and list missing evidence.
Keep the better answers in your notes.
FAQ
Which is free?
Both offer free-tier access with limits. Paid tiers raise limits and unlock features.
Should I start with an API instead?
No. Learn prompting in the browser first. Move to APIs (OpenAI, Anthropic, or a router) when a project needs automation.