What sets an audio file's size
Uncompressed audio such as WAV and AIFF stores every sample. Its size depends only on how many samples there are per second (sample rate), how many bits each sample uses (bit depth), how many channels there are, and how long it runs. Compressed formats like MP3, AAC and Ogg Vorbis instead target a bitrate, so their size depends only on the bitrate and the length.
The formula
compressed bytes = kbps × 1,000 ÷ 8 × seconds
MB = bytes ÷ 1,000,000 · MiB = bytes ÷ 1,048,576
bitrate (kbps) = sample rate × bit depth × channels ÷ 1,000
Example: a 3:30 song at CD quality
One stereo WAV file, 44.1 kHz, 16-bit, 3 minutes 30 seconds (210 seconds).
| Step | Result |
|---|---|
| Bytes: 44,100 × 2 × 2 × 210 | 37,044,000 |
| Size: 37,044,000 ÷ 1,000,000 | 37.04 MB |
| Binary: 37,044,000 ÷ 1,048,576 | 35.33 MiB |
| Bitrate: 44,100 × 16 × 2 ÷ 1,000 | 1,411.2 kbps |
| Per minute | 10.58 MB |
| Same length as 320 kbps MP3: 40,000 × 210 | 8.4 MB |
Storage per minute of stereo audio
| Format | Per minute | Per hour |
|---|---|---|
| WAV 44.1 kHz / 16-bit | 10.58 MB | 635 MB |
| WAV 48 kHz / 24-bit | 17.28 MB | 1.04 GB |
| WAV 96 kHz / 24-bit | 34.56 MB | 2.07 GB |
| MP3/AAC 320 kbps | 2.4 MB | 144 MB |
| MP3/AAC 128 kbps | 0.96 MB | 57.6 MB |
Tips
- Plan recording sessions by track count. 16 mono tracks at 48 kHz / 24-bit use about 138 MB per minute, or about 8.3 GB an hour.
- Lossless compression such as FLAC or ALAC typically shrinks WAV files to roughly half to two thirds of their size with no loss in quality.
- Higher sample rates double the storage for 96 kHz versus 48 kHz; use them when you need the extra headroom for processing, not by default.
- Windows shows MiB as "MB". If a file looks smaller in Explorer than here, compare with the binary units line.
Frequently asked questions
How big is a 3 minute WAV file?
At CD quality (44.1 kHz, 16-bit, stereo), audio takes about 10.58 MB per minute, so 3 minutes is about 31.75 MB. At 48 kHz and 24-bit stereo it's about 17.28 MB per minute, or 51.84 MB for 3 minutes.
How do you calculate WAV file size?
Multiply the sample rate by the bit depth divided by 8, by the number of channels, and by the length in seconds. That gives bytes. 44,100 × 2 bytes × 2 channels × 60 seconds = 10,584,000 bytes, about 10.58 MB per minute. The file header adds only a few dozen bytes.
How big is a 320 kbps MP3?
320 kilobits per second is 40,000 bytes per second, or 2.4 MB per minute. A 4 minute song is about 9.6 MB. At 128 kbps the same song is about 3.84 MB.
What is the difference between MB and MiB?
A megabyte (MB) is 1,000,000 bytes; a mebibyte (MiB) is 1,048,576 bytes. Drive makers and macOS use MB; Windows File Explorer shows MiB but labels them MB, which is why the same file can look about 5% smaller there.
Is there a size limit for WAV files?
Standard WAV files store their size in a 32-bit field, so they top out at about 4 GiB, roughly 6.7 hours of CD-quality stereo or about 4.1 hours at 48 kHz, 24-bit stereo. For longer recordings, recorders and DAWs switch to formats such as RF64 or split the take into several files.
Rates and figures last checked October 2026.
This calculator gives estimates for planning. Check current rates and product labels before you buy, list or file.