In short
An hour of meeting audio takes anything from about 15 MB to over 600 MB on a Mac, depending on the format, and a video recording of the same hour takes more.
Speech compresses well, so a recorder that saves compressed audio uses little space; one that saves uncompressed audio or video fills a disk quickly.
This guide gives rough sizes for the common formats, shows where to see what your recordings take, and covers freeing space without losing notes you want to keep.
Rough sizes per hour
The size of a recording is its bit rate multiplied by its length. For an hour:
| Format | Bit rate | About per hour |
|---|---|---|
| Uncompressed, CD quality (44.1 kHz, 16-bit, stereo) | 1,411 kbit/s | 635 MB |
| Uncompressed, speech quality (16 kHz, 16-bit, mono) | 256 kbit/s | 115 MB |
| Compressed, typical music quality (AAC 128 kbit/s) | 128 kbit/s | 58 MB |
| Compressed, speech (AAC 32 kbit/s, mono) | 32 kbit/s | 14 MB |
These follow from the arithmetic: bits per second × 3,600 seconds ÷ 8 bits per byte. Real files are a little larger, for headers and metadata.
Two things multiply the numbers:
- Several tracks. A recorder that keeps each side, or each participant, in its own file stores one file per track.
- Video. A video recording holds audio as well as the picture, and the picture takes most of the space. A screen share with a lot of movement produces larger files than a static one.
If your meeting app records video to your Mac, that is usually where the space goes, not the audio.
See what your recordings use
In macOS
Open System Settings › General › Storage to see what is using space by category, and Apple menu › About This Mac for a summary. For a specific folder, select it in Finder and choose File › Get Info.
Meeting apps keep recordings in different places. Zoom's local recordings, for example, go to a Zoom folder in Documents by default; how to record a Zoom meeting on a Mac covers where to change that.
In Notey
The status bar at the bottom of Notey's window shows Local data: the space taken by your recordings and by the database that holds transcripts and notes.
What Notey's recordings take
Notey saves each meeting as two compressed audio files, one for your microphone and one for the sound your Mac plays. Measured on real recordings, each track comes to about 15 MB an hour, so a one-hour meeting takes about 30 MB. A year of five one-hour meetings a week is roughly 8 GB.
While a meeting is being recorded, Notey writes the audio uncompressed first and compresses it when the meeting ends, so a recording in progress briefly takes more space than the finished file.
Two other things take space:
- Transcripts and notes are text, counted in Local data. A long meeting's transcript is a small fraction of its audio.
- The after-meeting recognisers that re-transcribe English meetings are about 1.2 GB in total, downloaded once. It is not part of the Local data figure.
Free up space
Delete what you do not need
In any tool, the recordings are the large part. Before deleting, decide whether you need the audio at all once a transcript exists. Many people keep the transcript and notes indefinitely and the audio for a few weeks.
In Notey, deleting a meeting removes its recording, transcript, notes and anything you asked Notey about it from this Mac. There is currently no way to delete only the recording and keep the rest. If you want to keep the text, export it first: Notey exports the summary, any note or everything as Markdown, and the transcript on its own as plain text, to the clipboard or a file. See exporting meeting notes as Markdown and transcripts as text.
If Notey's sync is on, deleting a meeting deletes it from your account and your other Macs too, and the confirmation says so first. Sync never copies recordings to your other Macs, so it does not use their disk space for audio.
Move old recordings off the Mac
For recordings from your meeting app, moving the folder to an external drive frees space without losing anything. Keep a note of where they went.
Keep an archive you can search
If the point of keeping recordings is being able to find what someone said, the transcript is what you search, not the audio. Building a searchable archive of your meetings covers organising that.
A note on running out of space mid-meeting
A recorder that runs out of disk space in the middle of a meeting may lose the end of it, or fail to finish writing the file. Keep at least a few gigabytes free before long recordings, and more if your meeting app records video to the Mac.
Frequently asked questions
How big is an hour of meeting audio?
It depends almost entirely on the format. Uncompressed CD-quality stereo is about 635 MB an hour. Compressed speech formats are far smaller; Notey's two tracks together come to about 30 MB an hour.
Why are video recordings of meetings so much larger?
Video carries many more bits per second than speech. A meeting's video file is usually several times the size of its audio, and screen shares with a lot of movement push it higher.
Can I delete a Notey recording and keep the transcript?
Not separately at present. Deleting a meeting in Notey removes its recording, transcript and notes together. To keep the text, export it as Markdown first.
Where does Notey keep recordings?
On your Mac, in Notey's folder inside your user Library. The status bar at the bottom of the window shows how much space Notey's local data takes.