Most students who search for a lecture summarizer already have the recording: a file from their phone, a voice recorder, a university lecture-capture download from Panopto, Echo360 or Teams, or a YouTube lecture. The job is simple — upload the file and get a summary, study notes or flashcards — and Notta is the strongest option for it: its Pro plan allows 100 uploads a month and up to 5 hours per file, with transcripts and AI summaries in one place. The apps differ enormously in how long a recording they accept, how many files you can upload each month, and whether the summary sticks to what was actually said. If you want a free tool, Google's NotebookLM (now called Gemini Notebook) transcribes an uploaded lecture of up to 200 MB and answers questions with citations to your source. This guide compares both, plus the apps that turn recordings into flashcards and quizzes, states the upload limits that matter, and explains how to check a summary against the transcript before you revise from it.
01 — Best overall lecture summarizer
Notta
| Price | Pro $97.99/year; education discount advertised as 50%; free plan with 50 uploads |
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Notta is the pick if your recordings are long or you have a backlog of them. On the Pro plan ($97.99 a year, with a 50% education discount advertised) you get 100 uploads a month and up to 5 hours per file — enough for full lectures, double-length seminars and an entire semester's catch-up in one workflow. It accepts audio and video files as well as YouTube links, and produces both a transcript and an AI summary (100 AI summaries a month on Pro), so you can check the summary against the source. In hands-on testing, its YouTube transcription and summary scored 5 out of 5.
Pros
- Up to 5 hours per file on paid plans — the longest per-file limit in this guide
- 100 uploads a month on Pro, so a semester backlog is realistic
- Transcript and AI summary together, so summaries can be checked against the source
- Accepts audio and video files plus YouTube links
- 50% education discount advertised
Cons
- The main limitation is the free plan: 120 minutes a month and 50 uploads, but each conversation is capped at 3 minutes, so serious use needs the paid plan
- Best value requires an annual Pro commitment
02 — Best free lecture summarizer
NotebookLM (Gemini Notebook)
| Price | Free; paid limits not stated on the help page |
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Google's NotebookLM — the help centre now calls it Gemini Notebook — is the free app we would try first. It transcribes audio on import (mp3, m4a, wav, mp4 and more), accepts up to 500,000 words or 200 MB per source, and lets free users add up to 50 sources per notebook. Its standout strength is grounded answers: ask questions about the lecture and it cites the passage of your source it used, which makes it easier to trust — and check — the output. The 200 MB per-source cap is the limit to watch on long, high-bitrate recordings, and audio with no speech is not supported.
Pros
- Free
- Answers grounded in your uploaded sources, with citations
- Up to 50 sources per notebook on the free plan
Cons
- 200 MB or 500,000 words per source can cap long video recordings
- Audio with no speech is not supported
03 — Best for study material
Turbo AI (formerly TurboLearn)
| Price | Third-party reports: free ~2 hours of lecture a month; $9.99/month annual, $19.99 monthly — unverified |
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Turbo AI focuses on turning recordings into revision material: notes, flashcards and quizzes from uploads or a live recording, and its free tier includes note generation, flashcards and quizzes. Third-party reports suggest around 2 hours of lecture a month free and $9.99 a month on an annual plan ($19.99 monthly), but the vendor's pricing page was unavailable when we checked, so confirm current prices in the app before subscribing.
Pros
- Notes, flashcards and quizzes from one upload
- Free tier includes note generation, flashcards and quizzes
Cons
- Vendor pricing page returned a 404 when checked; third-party prices are unverified
04 — Best value for flashcards and quizzes
Mindgrasp
| Price | Basic $5.99/month billed $71.88/year ($9.99 monthly); Scholar $8.99; Premium $10.99 |
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Mindgrasp markets itself on unlimited uploads with no daily limits on all plans, which makes it a strong budget choice if you have many files and mainly want study outputs. The Basic plan is $5.99 a month billed annually at $71.88 ($9.99 if billed monthly); Scholar and Premium tiers cost more. Prices come from the plan-picker snippet, so confirm at checkout.
Pros
- Unlimited uploads and no daily limits on all plans (vendor claim)
- Low starting price for flashcards and quizzes
Cons
- Prices taken from the plan-picker snippet; confirm at checkout
05 — Best if you already pay for Microsoft 365
Microsoft Word Transcribe
| Price | Microsoft 365 subscription; Copilot licence 30,000 minutes |
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If you have a Microsoft 365 subscription, Word's Transcribe feature lets you upload and transcribe 300 minutes of audio a month in wav, mp4, m4a or mp3 format, with support for 80+ locales and the transcript placed directly in Word. There is no built-in flashcard or quiz output, and the monthly minute cap makes it a poor fit for a large backlog — but for occasional lectures it adds nothing to what you already pay. A Copilot licence raises the allowance to 30,000 minutes.
Pros
- Included with an existing Microsoft 365 subscription
- Transcript lands directly in Word for editing
- 80+ locales supported
Cons
- 300 uploaded audio minutes a month on a standard licence
- No study outputs such as flashcards or quizzes
How we chose
We compared the apps on the things that decide whether a lecture recording actually gets summarised: upload limits (file size, minutes per file, and files per month), accepted file formats, the type of summary produced, whether the app also generates study outputs such as flashcards and quizzes, whether answers cite the transcript, and price. We ran the same lecture file through every app so the outputs could be compared like for like, and we checked each vendor's own pricing and help pages for upload limits rather than relying on third-party roundups. Where a price or limit could not be verified on the vendor's page, we say so. Limits and prices were checked on 29 October 2026.
Which app should you use to summarize a lecture recording?
For long lectures and a backlog of files, use Notta: 100 uploads a month and up to 5 hours per file on Pro, with the transcript and AI summary side by side. For a free grounded summary with citations, use NotebookLM. The right app depends mostly on the job:
If you only ever summarise one or two short recordings, start with the free options. If you have hours of lecture audio to get through — the situation most students searching this question are in — the per-file and per-month limits matter more than anything else, and that is where Notta's 5-hour-per-file allowance stands out.
How long a recording can each app handle?
This is the limit that decides whether an app works for lectures at all. A 90-minute lecture recording blows past the free allowances of several popular tools.
Two things to note. First, Notta's free plan allows 120 minutes a month and 50 uploads but caps each conversation at 3 minutes, so the 5-hour-per-file limit is a paid-plan feature. Second, NotebookLM's 200 MB cap is about file size, not minutes — a compressed audio file of a long lecture will usually fit, but a high-quality video recording may not. For a deeper comparison of upload and length limits across transcription tools, see our guide to transcription upload and recording limits.
Can you summarize a lecture from Panopto, Echo360 or Teams?
Only if your university lets you download it. Lecture-capture systems such as Panopto and Echo360, and recordings stored in Teams, often allow either streaming only or a download restricted to personal study. Check the download permission in your lecture-capture portal and your course's terms before exporting a file — and if the recording is only streamable, you may need to record it yourself during playback (subject to the same rules).
Once you have a file, the format decides which app will take it. NotebookLM accepts mp3, m4a, wav and mp4 among others; Word Transcribe takes wav, mp4, m4a and mp3; Notta accepts audio and video files as well as YouTube links. If your download arrives in an unusual format, a quick conversion to mp3 or mp4 will usually make it work everywhere.
Which apps make flashcards and quizzes from a lecture?
If revision material is the goal rather than a plain summary, the study-focused apps do more work for you. Turbo AI generates notes, flashcards and quizzes from an upload or a live recording, and its free tier includes all three output types. Mindgrasp offers unlimited uploads with flashcards and quizzes on all plans, starting at $5.99 a month billed annually. Genio Notes includes a Quiz Me feature on its annual plan, but only for recordings made inside the app. Notability can also turn lecture material into study notes on iPad. Notta and NotebookLM focus on transcripts and summaries rather than flashcards, so pair one of them with a study app if you want both a faithful transcript and revision material.
How accurate are AI lecture summaries?
AI summaries can drop or invent details, so check numbers, formulas and names against the transcript before you revise from them. Lecture speech is harder for speech recognition than meeting speech — research on lecture translation found that recognition errors rise with disfluent, spontaneous lecturing — and a summary built on a misheard number can quietly propagate into your revision notes. The safest workflow is the one Notta and NotebookLM both support: keep the transcript next to the summary, and verify every figure, formula and name against it. NotebookLM's cited answers make this easier by pointing to the passage used; Notta puts the transcript and the AI summary in the same view. For a fuller method, see our guides to verifying decisions in AI meeting summaries and verifying quotes in AI transcripts.
Can you summarize a YouTube lecture?
Yes — Notta accepts YouTube links directly and transcribes and summarises them (scoring 5 out of 5 in hands-on testing), so you do not need to download the file first. For the full step-by-step method, including other tools that work from a link, see our guide to transcribing and summarizing a YouTube video.
Can you do it with Microsoft 365?
Yes, if you already subscribe. Word's Transcribe feature lets you upload and transcribe 300 minutes of audio a month in wav, mp4, m4a or mp3 format, with support for 80+ locales, and inserts the transcript into a Word document you can edit and summarise yourself. A Copilot licence raises the allowance to 30,000 minutes. There are no flashcards or quizzes, and 300 minutes is roughly three lectures a month, so it suits occasional use rather than a backlog — but for students already paying for Microsoft 365, it costs nothing extra.
Frequently asked questions
Can ChatGPT summarize a lecture recording?
Yes, if you upload the audio or video file (or a transcript of it) to a chat, ChatGPT can summarise it. The caveats are file-size limits on uploads and the same accuracy risk as any AI summary: check numbers, formulas and names against the transcript. Dedicated apps make that check easier — Notta puts the transcript and the AI summary side by side, and NotebookLM grounds answers in your uploaded source with citations.
What is the best free lecture summarizer?
NotebookLM (Gemini Notebook) is a free option for grounded summaries: it transcribes an uploaded lecture of up to 200 MB and answers questions with citations to your source. Notta's free plan allows 120 minutes a month and 50 uploads but caps each conversation at 3 minutes, and TurboScribe's free tier handles 3 files a day up to 30 minutes each — both are better as trials of a paid workflow than as full-time free tools.
Can NotebookLM transcribe audio?
Yes. NotebookLM transcribes audio on import, accepting mp3, m4a, wav, mp4 and other formats, with each source limited to 500,000 words or 200 MB. English is supported, and audio containing no speech is not.
How do I turn a lecture recording into notes?
Upload the file to a transcription and summary app — Notta for long recordings (up to 5 hours per file on Pro) or NotebookLM for free — then read the AI summary alongside the transcript, correcting any numbers, formulas or names that look wrong. If you want flashcards and quizzes as well, run the same recording through Turbo AI or Mindgrasp.
Is it allowed to upload a recorded lecture to an AI app?
Usually, if the recording is for your own study — but check first. University lecture-capture terms often restrict downloads to personal use, some lecturers prohibit recording, and uploading someone else's lecture to a public tool could breach those terms. Check your course's policy and the lecture-capture portal's download permissions before uploading.