How big is a minute of CD quality audio?

About 10.1 MB. That is 44,100 samples a second, 16 bits each, two channels, which is 1,411 kilobits a second. The whole calculation is arithmetic rather than an estimate, because an uncompressed file stores every sample exactly as captured with nothing thrown away.

For recording, yes; for listening, not really. Each bit is about 6 dB of dynamic range, so 16 bits gives 96 dB, which is more than any listening environment resolves. The extra 8 bits buy headroom while tracking, so a quiet take can be lifted later without lifting the noise floor with it.

Why is my MP3 not exactly this size?

Because most encoders default to variable bitrate, spending more on complex passages and less on quiet ones. The figure here is for a constant bitrate, and a variable one lands near it across a whole track without matching within any part of it. Tags and embedded artwork add a little more on top.

Audio File Size Calculator

How big a recording will be.

Runs in your browserNothing you enter is uploaded, and it keeps working with the network off.

Format

uncompressedcompressed

Length in minutes

Sample rate in Hz

For an uncompressed file.

Bit depth

Channels

2 for stereo.

Bitrate in kbps

For a compressed file.

How big a recording will be.

How to use it

Pick the format. Uncompressed for WAV, compressed for MP3 or AAC.
Give the settings. Rate and depth, or just the bitrate.
Read the size. And the per minute figure, for planning.

When you would use this

For an uncompressed file this is not an estimate, it is arithmetic. Sample rate times bit depth times channels times seconds, divided by eight to get bytes. WAV and AIFF store every sample exactly as captured, so nothing is approximate. CD audio is the reference point everybody knows: 44,100 samples a second, 16 bits each, two channels, which is 1,411 kilobits a second and about 10.1 MB a minute. The two settings are worth understanding rather than copying. Bit depth is dynamic range, not detail. Each bit adds about 6 dB, so 16 bits gives 96 dB and 24 gives 144. Ninety six is beyond what any room resolves, so the extra bits are for recording rather than for listening: they are headroom, letting a quiet take be lifted afterwards without the noise floor coming up with it. Sample rate is bandwidth. A rate captures frequencies up to half itself, the Nyquist limit, so 44,100 reaches 22,050, which is past the top of human hearing. Rates above 48,000 are kept for processing headroom rather than for anything a listener hears directly. For a compressed file the size comes from the bitrate and the length, and the answer carries a caveat: nearly every encoder now defaults to variable bitrate, which spends more on complex passages. A constant bitrate figure lands near the real one over a whole track and not within any one part of it.

Questions

How big is a minute of CD quality audio?: About 10.1 MB. That is 44,100 samples a second, 16 bits each, two channels, which is 1,411 kilobits a second. The whole calculation is arithmetic rather than an estimate, because an uncompressed file stores every sample exactly as captured with nothing thrown away.
Is 24 bit worth it?: For recording, yes; for listening, not really. Each bit is about 6 dB of dynamic range, so 16 bits gives 96 dB, which is more than any listening environment resolves. The extra 8 bits buy headroom while tracking, so a quiet take can be lifted later without lifting the noise floor with it.
Why is my MP3 not exactly this size?: Because most encoders default to variable bitrate, spending more on complex passages and less on quiet ones. The figure here is for a constant bitrate, and a variable one lands near it across a whole track without matching within any part of it. Tags and embedded artwork add a little more on top.