Audio File Size Calculator

This utility calculates the size of audio files (both uncompressed, PCM/IEEE FP audio, such as “.WAV”, “.W64” “.AIFF/.AIF” and also compressed files such as MP3, WMA, AAC and OGG Vorbis), according to the recording duration and file settings you choose:

**N.B.** If you’re looking for a calculator to do the opposite (i.e. calculate duration from available space), then go here.

Audio File Size Calculator by Colin Crawley
Settings - Uncompressed (WAV, AIFF etc.)
Settings - Compressed (MP3, AAC etc.)
Uncompressed (WAV, AIFF etc.) 1411.2 kbps


Compressed (MP3, AAC etc.) 0 kbps



Enter the duration of your file in hours, minutes, seconds and milliseconds. Calculating the size of uncompressed files also requires the Sample Rate, Bit Depth and Channel information (but not the Bit Rate, which is automatically calculated). In addition to the duration, calculating the size of compressed files such as MP3 etc., requires only the Bit Rate information (in this case the Sample Rate, Bit Depth and Channel information is ignored).  For compressed files encoded with CBR (Constant Bit Rate), the displayed file size should be as accurate as possible (notwithstanding variables such as header information etc- see below). For compressed files encoded with VBR (Variable Bit Rate), the displayed file size can be slightly less accurate because in this case the bit rate can vary depending on the programme material.

Note that the file size reported by your device may vary slightly from that shown due to file allocation methods, possible differences in the amount of header information and/or the fact that some operating systems calculate hard disk space differently from others (e.g., some calculate it in binary and call 1kB 1024 bytes whilst others – and most hard drive manufacturers – calculate it in decimal and call 1kB 1000 bytes) – this calculator handles both methods.

If you find this useful and/or have any comments or suggestions then do let me know via the comment section below.


31 thoughts on “Audio File Size Calculator”

    1. Perhaps you’re looking at the “Uncompressed” (instead of the “Compressed”) output? When I enter 5min 17secs at 320kbps into my calculator I see a result of 12.68 MB (under the decimal “Compressed” result), which is correct.

      …unless I’ve misunderstood you (sorry if that’s the case). If you’re saying that you have an mp3 of 5min 17secs that is, in fact 28 MB in size, then I can only guess that it must be padded out with data extraneous to the audio (e.g. tons of extra metadata, or even just zeros!). Why that might be is anyone’s guess though.

      1. Yes, the actual file is that large. I guess I will need to look into the tags but I didn’t see anything suspicious by glancing at the file. I even removed 5mb of artwork and it’s still that big!

  1. I think the binary (2^10) to decimal (1000) converter is off. It just multiplies by 1.024, but that only works for KiB -> kB. For MiB -> MB it needs 1.024^2, for GiB -> GB 1.024^3, and so on, given that the binary prefix equivalent is 2^(10*n/3), where n is the power in 10^n.

  2. im trying to find out how often my RME is recording a sample pr second, im using 192 khz in 24 bit, how do I do that?

    I saw somewhere its every 2 ms, but I don’t think that’s right ?

    1. Hello Kim,

      Since your audio interface is set to record at a sample rate of 192kHz per second, then it is converting audio at a rate of 192000 samples per second.

      For specific information about your hardware, I suggest you contact RME directly.

    2. hi

      yes that’s in a full second but digital sampling doesn’t record all the time, as analog does, I think I got it now – 1/192000 x 1000 = 0,0052083333333333

      so that means it take a sample every 5 ms, someone correct me if im wrong 🙂

      1. Hi Kim,

        No, it’s MUCH more frequent than that – a sample taken only once every 5 milliseconds would result in a very inaccurate (and audibly chopped-up) digital representation of the audio!

        You have the correct calculation but you’re interpreting the result incorrectly (i.e. the result is in milliseconds, not in seconds). In fact, a simpler way to express this calculation would be 1/192 (because one second = one thousand milliseconds). Either way, the result is 0.005208333 milliseconds which is, of course, a tiny, tiny fraction of one millisecond.

Leave a Reply to Colin Crawley Cancel reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.