How to use it
- Choose uncompressed PCM for WAV, AIFF or raw recordings, or compressed for MP3, AAC, Ogg or Opus.
- For PCM pick the sample rate and bit depth and enter the number of channels. For compressed audio enter the bitrate in kbps.
- Enter the duration in minutes and seconds (90 minutes is fine in the minutes box).
- Read the size in MB, with MiB, the bitrate, and the size of one minute and one hour.
The formulas
PCM bitrate = sample rate × bit depth × channels
size in bytes = bitrate × seconds ÷ 8
For compressed audio the bitrate is the one you enter. MB here is 1,000,000 bytes and MiB 1,048,576 bytes.
Worked example
A 3 min 30 s song at CD quality:
- bitrate 44,100 × 16 × 2 = 1,411,200 bit/s = 1,411.2 kbps;
- 1,411,200 × 210 s ÷ 8 = 37,044,000 bytes = 37.04 MB (35.33 MiB);
- the same song as a 320 kbps MP3: 320,000 × 210 ÷ 8 = 8.4 MB.
Ten minutes of mono speech at 16 kHz and 16-bit: 16,000 × 16 × 1 = 256 kbps, 256,000 × 600 ÷ 8 = 19.2 MB.
Tips
- To plan a recording session, multiply the one-hour figure by the hours and add a margin.
- For a multitrack session, add the channels of every track: 16 mono tracks at 48 kHz and 24-bit is 16 channels.
- 32-bit here means 32-bit samples, integer or float; both take 4 bytes per sample.