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16-bit vs 24-bit audio recording: which should you choose?

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

Record at 24-bit when the level is unpredictable (a live DJ set, vinyl, a rehearsal) because the extra bits lower the noise floor and let you leave headroom without hiss. 16-bit is fine for anything already lossy or level-controlled, such as a stream capture or a voice note. The cost is disk: 24-bit 48 kHz is 16.5 MB per minute, 16-bit is 11.0 MB, a 50 percent difference measured on real files.

What is the difference between 16-bit and 24-bit audio?

Bit depth sets how finely each sample's level is stored, which sets the gap between the loudest possible signal and the quantization noise. The signal-to-quantization-noise ratio is about 1.76 + 6.02 x bits dB, which gives roughly 98 dB for 16-bit and 146 dB for 24-bit (Wikipedia, Audio bit depth). Every extra bit adds about 6 dB.

Those are theoretical ceilings. No converter in a USB interface reaches 146 dB; the analog stages set the real floor well below that. But the practical effect holds: a 24-bit recording made 20 dB below full scale still has a lower noise floor than a 16-bit recording made at the same level, and the file gives you room to raise the level later without pulling the floor up audibly. Sample rate is a separate decision, covered in 44.1 kHz vs 48 kHz.

Does 24-bit sound better?

Not on playback. A finished, well-leveled 16-bit file is transparent for listening; that is what audio CDs are. The advantage of 24-bit is during recording, before the level is known. If a DJ pushes the master 6 dB hotter than the soundcheck, a track recorded with plenty of headroom survives; a track recorded close to full scale clips, and clipping cannot be undone (see why does my recording sound distorted or clipped). With 24-bit you can set the gain conservatively and pay almost nothing in noise.

For system audio the source is already digital. What macOS plays from YouTube, Spotify or a Zoom call arrives as a stream of samples; capturing it at 24-bit stores those samples with more precision than the source had, which adds nothing but also loses nothing. AirCheck always captures at 24-bit and converts once at the end, so the choice is only about what you keep.

How much bigger is a 24-bit file?

Exactly 50 percent bigger for the same sample rate, because each sample takes three bytes instead of two. Measured on 45 real recordings on the author's Mac:

In hours per 10 GB that is 10.3 h at 24-bit 48 kHz against 15.6 h at 16-bit 48 kHz. A 2-hour set is 1.98 GB vs 1.32 GB. Both are small next to a video screen recording, and both convert to a 2.4 MB per minute MP3 in the same way. The full size table with hours per GB is in how big is an audio recording per minute.

When is 16-bit good enough?

Choose 16-bit when at least one of these is true:

Choose 24-bit when a human sets the gain and the level can jump: DJ mixers, turntables, live instruments, interviews on a microphone through an interface. Convert down afterwards with afconvert -f WAVE -d LEI16 in.wav out16.wav if you need the smaller file; that direction is safe. Going up from 16 to 24-bit gains nothing.

16-bit vs 24-bit vs MP3 for a stereo 48 kHz recording

OptionTheoretical SQNR (dB)MB per minuteGB per hourHours per 10 GBSafe for unpredictable live levels
16-bit PCM9811.00.6415.6no
24-bit PCM14616.50.9710.3yes
MP3 320 kbpsnot applicable (lossy)2.40.1471no

SQNR from the 1.76 + 6.02 x bits formula (Wikipedia); sizes measured on real files.

Where AirCheck fits

AirCheck ($39, macOS 14 or newer) records every take at 24-bit whatever you plan to keep, then converts once when you stop into WAV 16-bit, WAV 24-bit or MP3 320 kbps. A DJ recording through a Focusrite Scarlett 8i6 gets the headroom of 24-bit at 16.5 MB per minute; someone capturing a lecture stream can pick 16-bit WAV at 11.0 MB per minute or MP3 at 2.4 MB per minute from the same app without touching Terminal.

When you do not need it: For a microphone-only voice note, QuickTime Player's New Audio Recording is free and its quality setting is enough. If you need to mix a mic with app audio in one take, Audio Hijack does that and AirCheck does not.

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

Is 24-bit worth it for recording?

Yes when a person sets the gain and the level might jump, because the noise floor is far lower and you can leave headroom. Not when the source is a lossy stream or a call; then 16-bit at 11.0 MB per minute captures everything the source had.

What is the dynamic range of 16-bit vs 24-bit audio?

About 98 dB for 16-bit and about 146 dB for 24-bit, using the 1.76 + 6.02 x bits formula. Real converters do not reach the 24-bit figure; the analog electronics set the practical limit.

Does 24-bit make the file bigger?

By 50 percent at the same sample rate: 16.5 MB per minute against 11.0 MB at 48 kHz, measured on real files. An hour is 0.97 GB versus 0.64 GB.

Can I convert 24-bit to 16-bit later?

Yes, losslessly in the sense that nothing you can hear is lost at normal levels: afconvert -f WAVE -d LEI16 in.wav out.wav. The file drops from 16.5 to 11.0 MB per minute. The reverse conversion works too but adds no real information.

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