Best for: Write
ChatGPT
The best-known AI chat assistant: ask anything, get a written answer.
Best for: Understand topics, notes and sources faster.
Upload your notes or PDFs and chat with them, or hear them as a podcast.
Google's research notebook (formerly NotebookLM). You add your own sources (PDFs, docs, links) and it answers only from them, makes study guides and can turn them into an audio summary you can listen to.
The free limits cover most students.
Without a paid AI plan you get up to 100 notebooks and 50 sources per notebook (per Google's help page); paid Google AI plans raise these limits.
Source: Gemini Notebook (NotebookLM)'s own pricing page, checked Nov 2026. Plans change; confirm before you pay.
Best for: Write
The best-known AI chat assistant: ask anything, get a written answer.
Best for: Study & research
An AI search engine that answers with sources you can click.
Best for: Write
A careful, clear AI writing and thinking partner from Anthropic.