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How to record a lecture on a Mac

Tested on macOS 26.4.1 (Tahoe), Apple M3 Max, 3 Sept 2026. Updated 2026-09-03.

You can record a lecture on a Mac two ways. In the room, record the microphone with Voice Memos or QuickTime Player (File > New Audio Recording). Online, record what the Mac plays with a system audio recorder built on ScreenCaptureKit, because QuickTime cannot capture playback. A 90-minute lecture is 216 MB as MP3 320 kbps or 990 MB as 16-bit 48 kHz WAV.

Are you in the lecture hall or watching it online?

This decides everything else. The two situations use different inputs and different tools.

One limit applies to every system audio recorder, including AirCheck: the capture contains what the Mac plays, not what your own microphone hears. If you ask a question out loud in an online lecture, your voice is not in the file. For a lecture that is fine, because the lecturer's voice comes through the stream. For a seminar where you speak, see recording computer audio and the mic at the same time.

How do I record a lecture on my Mac with the microphone?

Voice Memos is the fastest option and it transcribes the result on macOS 15 or later with Apple silicon.

  1. Open Voice Memos. In Settings, set Audio Quality to Lossless. Apple describes the two choices as "Compressed (for lower-quality, smaller files) or Lossless (for high-quality, larger files)".
  2. Put the Mac as close to the lecturer as the room allows. The built-in mic picks up keyboard noise and fan noise before it picks up a voice 10 meters away.
  3. Click Record. Click Done when the lecture ends. The file is named "New Recording" unless location naming is on.

QuickTime Player gives you a normal file on disk instead of a Voice Memos library entry. Choose File > New Audio Recording, click the arrow next to the record button, pick the mic and the quality. Apple lists "Maximum: 44100 Hz, uncompressed Linear PCM 24-bit AIFF-C audio" and "High: 44100 Hz AAC audio". Save with File > Save when done. Full steps are in recording audio with QuickTime Player.

If the Mac has no sound in the recording at all, the app was never granted Microphone access. Fix it in System Settings > Privacy & Security > Microphone.

How to record lectures on Mac with audio from an online stream?

For a live stream or a recorded lecture in a browser you record system audio. Tested sequence with AirCheck on macOS 26.4.1:

  1. Open AirCheck and choose System Audio as the source. The first time, macOS asks for Screen Recording permission (System Settings > Privacy & Security > Screen & System Audio Recording). This is a one-time approval; no driver is installed and Audio MIDI Setup is untouched.
  2. Choose the export format. MP3 320 kbps is the sensible choice for speech you will transcribe. Pick WAV 16-bit if you want to edit first.
  3. Press record, then start the lecture. AirCheck excludes its own playback, and everything else the Mac plays goes into the file, including notification sounds. Mute Messages and Mail for the duration.
  4. Stop at the end. The file lands in ~/Music/AirCheck.

If a stream stalls, the watchdog restarts capture into the same file after 5 seconds without audio, so a network hiccup does not end the take. Free alternatives exist: OBS Studio captures desktop audio on macOS 13 and newer, but it writes a video container (mkv or mp4) and needs a scene set up first. BlackHole works too, but it needs a Multi-Output Device or your speakers go silent. See recording Mac audio without BlackHole.

How big is a 90-minute lecture recording and will my MacBook battery last?

File size depends only on the format, not on the tool. The numbers below come from 45 real recordings measured on the author's Mac.

For speech that goes into a transcription tool, MP3 320 is enough and it keeps a full semester on a laptop drive. Keep 24-bit for music or for anything you will edit heavily; the difference is explained on the 16-bit vs 24-bit page in the formats guides.

Battery: audio recording is light work compared with video playback. Apple rates the current MacBook Air at "Up to 18 hours video streaming" and "Up to 15 hours wireless web" in its own January 2026 testing, so a 90-minute in-room recording is not a battery problem. The real risk is sleep. On a MacBook, closing the lid stops the recording, and an idle display can trigger sleep. Keep the lid open, lower brightness, and on power set System Settings > Battery > Options > "Prevent automatic sleeping on power adapter when the display is off". Details in Mac recording stops when the display sleeps.

Maximum: 44100 Hz, uncompressed Linear PCM 24-bit AIFF-C audio

Apple, QuickTime Player User Guide, Record audio

Recording a 90-minute lecture on a Mac: what each option gives you

OptionCaptures the room (mic)Captures an online streamFile you getSize for 90 minPrice
Voice MemosyesnoVoice Memos library entry (AAC or Lossless)not measuredfree
QuickTime Player audio recordingyesnoAIFF-C 24-bit 44.1 kHz or AAC1,359 MB at 24-bitfree
OBS Studioyesyes (macOS 13+)mkv or mp4 videodepends on video settingsfree
AirCheckyesyes (ScreenCaptureKit)WAV 16/24-bit or MP3 320216 MB as MP3, 990 MB as 16-bit WAV$39

Sizes for WAV and MP3 are computed from the measured MB per minute in the AirCheck library (16-bit 48 kHz: 11.0 MB/min, MP3 320: 2.4 MB/min, 24-bit 44.1 kHz: 15.1 MB/min).

Where AirCheck fits

AirCheck ($39, macOS 14 or newer) is for the online case: a streamed or recorded lecture that QuickTime cannot hear. It records system audio through ScreenCaptureKit with no driver, restarts capture into the same file if the stream stalls, and exports straight to MP3 320 so a 90-minute lecture is 216 MB. For in-room recording it also lists any mic or interface, but there it is one option among free ones.

When you do not need it: If you are sitting in the lecture hall, Voice Memos or QuickTime with the built-in mic is free and enough. If the lecturer already posts a recording, download that instead of capturing it.

AirCheck records what your Mac plays, or any input, to one file. $39 once.

Buy AirCheck for $39

macOS 14 or newer. One-off payment. Fourteen-day refund, no questions asked.

Questions people ask

Can you record lectures on a MacBook Air?

Yes. Any MacBook Air with macOS 14 or newer can record the built-in mic with Voice Memos or QuickTime, and can record system audio through ScreenCaptureKit with an app such as AirCheck or OBS. Keep the lid open; closing it puts the Mac to sleep and ends the take.

How to screen record a lecture on Mac with sound?

Press Shift-Command-5, choose Record Entire Screen, and pick a microphone under Options. You get a .mov video file with the mic track; playback is not included. If you only want audio, a system audio recorder gives a smaller file; see recording audio only without video.

Is it legal to record a lecture?

That depends on your country and your institution's rules, and this page is not legal advice. Many universities allow personal recordings with the lecturer's permission. Ask first, record for your own study, and do not publish the file.

How do I turn a lecture recording into notes?

On macOS 15 or later with Apple silicon, Voice Memos transcribes its own recordings. For a WAV or MP3 from another app, MacWhisper (free tier) transcribes locally. Steps are in how to transcribe audio on a Mac.

Sources

Hannes Hennerbichler builds AirCheck and records his own DJ sets with it through a Focusrite Scarlett 8i6. Every step on this page was run on the macOS version stated above. Drafted with AI assistance, checked and edited by the author. About