About this tool
Uncompressed audio (PCM, e.g. in WAV or AIFF files) needs exactly sample rate × bit depth × channels × duration of storage. The calculator turns that into the file size including the 44-byte WAV header and the bitrate – one hour in CD quality (44.1 kHz, 16 bit, stereo) is 635.04 MB at 1411.2 kbit/s. If a file grows beyond 4 GiB, it points out the limit of classic WAV files.
For MP3, AAC and Opus only the bitrate matters: 4 minutes at 320 kbit/s are 9.6 MB. The other way round, the “Recording time” mode tells you how long you can record onto a memory card – 32 GB hold about 30.9 hours at 48 kHz, 24 bit, stereo. All sizes are shown in decimal (MB) and binary units (MiB). For download times, see the Bandwidth Calculator.
How it works
- Choose the mode: WAV / PCM, MP3 / AAC / Opus or recording time.
- Enter the duration or the storage size and pick the format – the quick buttons set e.g. CD quality or MP3 320.
- Read the file size, bitrate or recording time; the table compares the duration in common formats.
Frequently asked questions
How do you calculate the size of a WAV file?
Sample rate × bit depth ÷ 8 × channels × seconds gives the audio data in bytes, plus a 44-byte header. One minute of CD audio: 44,100 × 16 ÷ 8 × 2 × 60 = 10,584,000 bytes, about 10.58 MB. At 48 kHz, 24 bit and 5.1 (6 channels) it is 51.84 MB per minute.
Why does a CD have 1411.2 kbit/s?
An audio CD stores 44,100 samples per second at 16 bits for two channels: 44,100 × 16 × 2 = 1,411,200 bit/s. An MP3 at 320 kbit/s therefore uses less than a quarter of that data rate, one at 128 kbit/s about an eleventh.
What is the difference between MB and MiB?
An MB (megabyte) is 1,000,000 bytes, an MiB (mebibyte) 1,048,576 bytes. Storage vendors count in decimal, many operating systems in binary. That is why your computer may show a 635.04 MB file as 605.62 MiB. The calculator shows both values.
Does it matter whether 32 bit is integer or float?
Not for the file size: both need 4 bytes per sample. 32-bit float, however, offers enormous headroom – recordings that went over 0 dBFS can be turned down afterwards without clipping. That is why many field recorders record in 32-bit float.
Why is my MP3 a bit larger than calculated?
The calculator only counts the audio data at a constant bitrate. ID3 tags, embedded cover art and container overhead come on top. With variable bitrate (VBR) the size depends on the material; enter the average bitrate.