Find out how much space a song or a recording takes before you export it. Pick a format and enter the length: for MP3, AAC or Ogg choose the bitrate, and for WAV, AIFF or FLAC choose the sample rate, bit depth and channels. The size of WAV and AIFF audio is exact math (sample rate times bit depth times channels times seconds), MP3 and AAC sizes follow from the bitrate, and FLAC is shown as an estimate from a typical compression ratio, since its size depends on the music. Turn it around to get the bitrate of a file from its size and length. A reference table shows a 3 minute song in common formats, and a short guide explains kbps, sample rate and bit depth. It runs in your browser, needs no sign in and costs nothing.
A 3 minute stereo WAV at 44.1 kHz and 16 bit holds 31,752,000 bytes of audio, about 31.75 MB (30.28 MiB). At 48 kHz and 24 bit it is 51,840,000 bytes, about 51.84 MB. The file adds a small header on top, usually under 100 bytes.
320 kbps is 320,000 bits, or 40,000 bytes, every second. One minute is 2,400,000 bytes, which is 2.4 MB, so a 3 minute song is about 7.2 MB. At 128 kbps a minute is 0.96 MB. Tags and cover art add a little to that.
Multiply the sample rate by the bit depth divided by 8, by the number of channels and by the length in seconds. For CD quality stereo that is 44,100 times 2 bytes times 2 channels, or 176,400 bytes per second, about 10.58 MB per minute.
Kilobits per second: how much data the file spends on each second of audio. 1 kbps is 1,000 bits per second, and 8 bits make a byte, so 320 kbps is 40 KB per second. For MP3 and AAC a higher bitrate keeps more detail. Uncompressed CD quality audio runs at 1,411.2 kbps.
FLAC is lossless, so it keeps every bit of the WAV, but it packs it smaller. For typical music it lands at about 50% to 70% of the WAV size, and the calculator uses 60% as its single estimate. Quiet or sparse music shrinks more, dense or noisy music less, so treat the number as a guide.
Switch to Size to bitrate, enter the file size and the length, and the calculator divides the bits by the seconds. A 7.2 MB file that plays for 3 minutes works out to 320 kbps. Tags and artwork make the result read slightly high.
There are two kinds of megabyte. Encoders, macOS and storage makers use 1 MB = 1,000,000 bytes, while Windows shows sizes in units of 1,048,576 bytes (MiB) but labels them MB. The calculator shows both, so a file of 31,752,000 bytes reads 31.75 MB here and 30.28 in Windows.
Yes. It is free, needs no sign in and runs in your browser. To actually change a file's format, sample rate or bitrate, use the Audio File Converter, and to check a finished master before release, use Release Ready Check.