Two different shapes of tool
The clearest way to choose is to look at the unit each product is built around.
Gemini Notebook is built around the notebook. You create one for a project and add sources to it: PDFs, websites, YouTube videos, audio, text. Google’s help center says a notebook can hold up to 50 sources without a paid plan. You then chat across all of them, and the answers cite the sources they came from. It can also turn those sources into Audio Overviews, Video Overviews, flashcards and quizzes.
SumAI is built around the summary. You paste one link or pick one PDF, choose a style and a language, and get a structured summary in seconds. Around that summary sit the tools for that one source: key moments, Ask AI, a mind map, a quiz, flashcards and the transcript.
Neither approach is better in general. A notebook is the right shape for a dissertation. A summary is the right shape for “what did this ninety-minute talk say?”
Where Gemini Notebook is stronger
- Many sources at once. This is its defining feature, and SumAI does not do it. Each SumAI summary covers one source.
- Citations across sources. Answers point back to the passages they are based on.
- Audio and Video Overviews. A generated discussion of your material is a distinctive way to absorb it. SumAI’s Listen feature reads a summary aloud, which is a simpler thing.
- Reach. It runs on the web and Android as well as on iPhone and iPad.
- Cost. It is free with a Google Account, with paid Google AI plans raising the limits.
Where SumAI is stronger
- Speed to a summary. There is no notebook to create. Share a video from the YouTube app and read.
- Depth on demand. Five summary styles let you decide in advance whether you want a paragraph or a study guide.
- Video navigation. Chapters and key moments carry timestamps that jump into the video. Google’s help page describes YouTube sources as transcript text.
- Mind maps on iPhone. As of November 2026, Google says mind maps are not yet available in its iPhone app.
- No account. SumAI works without signing in.
What they share
Both need a YouTube video to have captions. Google’s help page says only public videos with captions are supported and that videos uploaded less than 72 hours ago may fail to import. SumAI’s App Store listing states that videos need captions or auto-generated subtitles.
Both generate flashcards and quizzes, both support many languages, and both produce AI output that should be checked against the source when it matters.
A reasonable way to use both
Use SumAI on your phone for everything that arrives one item at a time: the video a colleague sent, the article you saved, the paper you are deciding whether to read. Move the few sources that matter into a Gemini Notebook when you need to work across them.
