How this instrument works
Uncompressed digital audio stores a fixed number of amplitude samples every second, and each sample takes a fixed number of bits to represent. Multiply the sample rate by the bit depth, by the channel count, and by the duration in seconds, and you get the total number of bits the recording needs; divide by eight for bytes, and by another million for megabytes. There is no compression, prediction, or trickery in a raw PCM or WAV file — the size is pure arithmetic.
The three quality settings trade off directly against file size. CD-quality audio samples 44,100 times a second at 16 bits per sample; professional recording sessions often step up to 48,000 or 96,000 Hz and 24-bit depth for extra headroom, at a proportional cost in storage. Doubling any one of sample rate, bit depth or channel count doubles the file size, because the formula multiplies them together with nothing to soften the effect.
This calculator estimates the size of an uncompressed file — a .wav or .aiff, essentially. Compressed formats like MP3 or AAC apply psychoacoustic modeling to discard audio detail humans barely notice, typically shrinking the same recording to a tenth of this size or less. This instrument won't predict a compressed file's size, only the raw PCM data a recording, editing or mastering session is actually pushing around before export.
- Enter Sample rate in Hz — 44,100 for CD quality, 48,000 for most video and streaming work, or 96,000 for high-resolution recording.
- Enter Bit depth in bits — 16-bit for consumer playback, 24-bit for recording and mixing headroom.
- Enter Channels — 1 for mono, 2 for stereo, or more for multichannel and surround recordings.
- Enter Duration in seconds — convert minutes to seconds first, since a 3-minute track is 180 seconds.
- Read File size (MB) — the uncompressed storage this recording occupies as raw PCM data, before any compression is applied.
Worked example — 3 minutes of CD-quality stereo audio
Enter 44,100 Hz for sample rate, 16 bits for bit depth, 2 channels for stereo, and 180 seconds for duration — three minutes of standard CD-quality audio. Multiplying gives 44,100 x 16 x 2 x 180 = 254,016,000 bits of raw data.
Dividing by 8,000,000 to convert bits into megabytes, File size (MB) reads 31.752 MB. That is the size of the uncompressed .wav file this recording would produce — export the same three minutes as a 320kbps MP3 instead and it would shrink to roughly 7 MB, because compression discards the redundancy this raw calculation counts in full.
Questions
How big is a 3-minute CD-quality stereo audio file?
About 31.75 MB uncompressed. Three minutes, or 180 seconds, of 44,100 Hz, 16-bit, stereo audio works out to (44,100 x 16 x 2 x 180) / 8,000,000 = 31.752 MB as a raw .wav file — compressing the same clip to MP3 would shrink it to roughly a tenth of that size.
Why does raising the bit depth from 16-bit to 24-bit increase file size so much?
Because file size scales directly with bit depth: moving from 16 bits to 24 bits per sample is a 50% increase in the size of every single sample, multiplied across every sample in the recording. A minute of 48,000 Hz stereo audio grows from about 11.52 MB at 16-bit to 17.28 MB at 24-bit for exactly this reason — no compression is involved, it's pure per-sample arithmetic.
Does this calculate MP3 or other compressed file sizes?
No. This instrument calculates the size of uncompressed PCM audio, the kind stored in a .wav or .aiff file. Formats like MP3, AAC and Opus use psychoacoustic compression to discard audio detail the ear barely perceives, typically producing a file somewhere between a fifth and a tenth of the uncompressed size calculated here, depending on the bitrate chosen.
How much smaller is mono audio than stereo?
Exactly half the size, because the channel count is a direct multiplier in the formula. Recording the same five minutes of 44,100 Hz, 16-bit audio in mono instead of stereo drops the file from roughly 52.92 MB to 26.46 MB — useful to know when a voice recording doesn't need two channels of near-identical data.
What sample rate and bit depth should I record at?
For most music and podcast recording, 44,100 or 48,000 Hz at 16 or 24 bits per sample is standard. A 48,000 Hz, 24-bit setting is a common choice for professional recording sessions that need mixing headroom, while 44,100 Hz, 16-bit is the CD-quality standard most listeners will ultimately hear.