Most note-app comparisons are written for knowledge workers, so they rank tools on databases, backlinks and web clipping. If your notes are full of integrals, circuit diagrams and hastily copied proofs, almost none of that matters. Three things do.
The three criteria that actually decide it
1. Can you get an equation into it at lecture speed? A typed superscript, subscript or fraction takes several seconds per symbol. A lecturer covers a board in ninety seconds. Any app whose only math input is typed LaTeX will lose you the middle of the derivation, which is the part you needed.
2. Can you draw? Diagrams, graphs, free-body sketches, geometry figures and arrows connecting two lines of algebra are not decoration in a technical subject. An app without free-form ink or a decent drawing canvas is not a math note app.
3. Will you still have the notes in three years? Proprietary formats and subscription lock-in matter more than they seem in week one. Ask what happens to your files if you stop paying.
Everything else — templates, AI summaries, sync speed — is secondary.
If you write with a stylus
OneNote is the default recommendation, and it is free. An infinite canvas rather than a page, so a derivation that overruns has somewhere to go; excellent ink with palm rejection; you can mix typed text, handwriting and images on one page; and it has ink-to-math conversion that turns a handwritten equation into a typed one, which is genuinely useful when it works and merely fine when it does not. Sync across Windows, iPad, Mac and Android is solid. Weaknesses: search inside handwriting is inconsistent, and the Mac version has always lagged the Windows one.
GoodNotes and Notability (iPad, paid) are better feeling products. GoodNotes has the best handwriting search in the category and converts handwritten math well. Notability's audio recording, which syncs the recording to what you were writing at that moment, is the single best feature in any note app for lecture-heavy courses — tap a line of notes and hear what the lecturer was saying as you wrote it. Both are paginated rather than infinite-canvas, which suits annotating lecture PDFs and constrains sprawling algebra.
Xournal++ is free, open source and cross-platform, and is the right answer if you use Linux or refuse subscriptions.
Apple Notes has quietly become adequate: free, instant, syncs, handles ink. Not organised enough for a full degree, and perfectly fine for a single course.
If you type
Obsidian is the strongest choice for technical notes. It renders LaTeX natively, so equations look right, and it stores everything as plain Markdown files in a folder you control — which means your notes outlive the app, the subscription and the company. Linking between notes suits mathematics unusually well, where a definition genuinely is referenced from a dozen later results. Free for personal use. The cost is setup time and a bias toward text: drawing requires a plugin and is never as good as ink.
Notion is better at organising a degree than at capturing a lecture. Databases for assignments and deadlines, clean shared pages for group work, and LaTeX support that renders correctly but is slow to type into. Choose it if your bottleneck is organisation rather than equation capture. Offline support remains its weak point.
LaTeX proper, via Overleaf or a local editor, is what upper-year math majors often end up doing. Typing notes in LaTeX is slow at first and then surprisingly fast, produces beautiful and permanent documents, and forces you to understand structure. It is genuinely a bad idea for a first-year student taking five courses and a good one for someone writing up a proof-heavy course they will reread.
Typst is the newer alternative with much lighter syntax and near-instant preview. Worth a look if LaTeX has previously defeated you.
The app most people should add, which is not a note app
Notes you never revisit have almost no effect on grades. The step that does is turning them into retrieval practice: Anki, free, with a card for each definition, formula and "why does this step follow" you did not immediately know. Twenty minutes of note-taking plus ten minutes of card-making beats an hour of beautiful notes.
What to actually write down in a math lecture
Verbatim transcription is the common failure and it feels productive. Better:
- Write the statement of every definition and theorem exactly.
- For proofs and worked examples, write the structure and the turning point, not every algebraic line. The line where the trick happens is what you will need; the expansion afterwards you can redo.
- Keep a running margin column for "I did not follow this". It is the most valuable thing in the notebook, and it is the list you take to office hours.
- Leave white space. You will add to these notes later, and pages with no room stay unrevised.
Where a solver fits into a notes workflow
When you review and hit one of those margin marks, you need the missing steps, and the lecturer is not there. Working the problem through a step-by-step solver — an equation solver, a derivative calculator, a trig identity simplifier — and pasting the specific step you were missing into your notes closes the loop. That is a narrow, honest use: AI-Math is a solver, not a note app, and it should not be anywhere in this comparison except at this one join.
A recommendation, briefly
iPad and a stylus: GoodNotes, or Notability if your lectures are dense and you want the audio sync. Any device, free: OneNote. Typed notes you want to keep for a decade: Obsidian. Organising a whole degree: Notion, with something else for lectures. Add Anki regardless of which you pick.
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