Audio duration equals the file size in bits divided by the bitrate in bits per second. A 4.8 MB MP3 at 128 kbps holds 38,400,000 bits, and 38,400,000 ÷ 128,000 gives 300 seconds, or 5:00. For WAV files, the bitrate is sample rate × bit depth × channels.
Podcast editors, archivists and anyone checking an upload limit often know a file's size but not its running time, or want to predict the length that fits inside a storage budget. This calculator turns size into playing time two ways: from the bitrate of a compressed file such as MP3, AAC or Opus, or from the sample rate, bit depth and channel count of uncompressed PCM audio like WAV or AIFF. It shows the time as h:mm:ss, the total seconds and minutes, the bitrate it used and how many megabytes each minute takes. Container headers, cover art and ID3 tags add a few kilobytes that are not audio, so very short files come out slightly longer than they really play.
Choose Compressed for MP3, AAC or Opus files, or Uncompressed for WAV and AIFF.
Type the size and set its unit in the box: KB, MB and GB are decimal, KiB, MiB and GiB are binary.
Enter the kbps for a compressed file; for WAV, choose the sample rate, bit depth and number of channels.
The duration, total seconds and MB per minute update as you type, with the working shown below.
Result Playing time: 1:00
Total seconds: 60
Total minutes: 1
Bitrate used (kbps): 1,411.2
MB per minute: 10.584
Stereo 16-bit audio at 44.1 kHz uses 176,400 bytes a second, so this file holds exactly one minute.
Result Playing time: 5:00
Total seconds: 300
Total minutes: 5
Bitrate used (kbps): 128
MB per minute: 0.96
A typical song-length MP3: 128 kbps works out to 0.96 MB per minute.
Result Playing time: 1:09:27
Total seconds: 4,166.67
Total minutes: 69.44
Bitrate used (kbps): 192
MB per minute: 1.44
800,000,000 bits at 192,000 bit/s is 4,166.67 seconds, just under 70 minutes.
t = (S × 8) ÷ R, with R = f × b × c for PCM
tSRf, b, cThe size is converted to bytes (1 MB = 1,000,000 bytes, 1 MiB = 1,048,576 bytes) and multiplied by 8 to get bits. A bitrate in kbps means thousands of bits per second, so 128 kbps is 128,000 bit/s. Dividing bits by bits per second gives seconds. Uncompressed PCM has a fixed rate: CD audio at 44.1 kHz, 16-bit stereo runs at 1,411.2 kbps, or about 10.58 MB per minute.
At 128 kbps one minute is 128,000 × 60 ÷ 8 = 960,000 bytes, about 0.96 MB. At 320 kbps it rises to 2.4 MB per minute, and at 64 kbps, common for spoken podcasts, it falls to 0.48 MB.
CD-quality WAV (44.1 kHz, 16-bit, stereo) uses 176,400 bytes per second, which is 10.584 MB per minute. A 48 kHz, 24-bit stereo recording uses 288,000 bytes a second, or 17.28 MB per minute.
The file includes headers, ID3 tags and sometimes embedded cover art. A 500 KB album image inside an MP3 counts toward the size but holds no sound, so the estimate runs long by the time that image would take at the file's bitrate.
MB is decimal, 1,000,000 bytes; MiB is binary, 1,048,576 bytes, about 4.9% larger. Windows shows MiB but labels it MB, while macOS shows true decimal MB. Pick the unit that matches where you read the size.
Yes, as an estimate, if you enter the average bitrate. VBR encoders change the rate from frame to frame, so the nominal setting (for example V0 at around 245 kbps) only approximates the average for a given track.
Yes. Enter the free space as the file size and the format you record in. A 32 GB card holds about 50 hours of CD-quality WAV, or around 555 hours of 128 kbps MP3.
Using this tool in an assignment, article or report? Copy a citation, or a link for your website.
Tools Directory Editorial Team. (2026, October 24). Audio Duration Calculator. Tools Directory. Retrieved October 26, 2026, from https://tools.milunir.com/video-audio/media-utilities/audio-duration-calculator/
Tools Directory Editorial Team. “Audio Duration Calculator.” Tools Directory, 24 Oct. 2026, https://tools.milunir.com/video-audio/media-utilities/audio-duration-calculator/. Accessed 26 Oct. 2026.
Tools Directory Editorial Team. “Audio Duration Calculator.” Tools Directory. Last modified October 24, 2026. Accessed October 26, 2026. https://tools.milunir.com/video-audio/media-utilities/audio-duration-calculator/.
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