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Audio File Size Calculator

Video & AudioMedia Utilities
Audio format
Audio type
Length
File size (MB) —
Size in MiB (binary)
—
Size in GB
—
Bytes
—
Bitrate (kbps)
—
MB per minute
—

Audio file size equals bitrate times duration divided by 8. A 4-minute MP3 at 128 kbps is 128,000 × 240 ÷ 8 = 3,840,000 bytes, or 3.84 MB. For uncompressed WAV, the bitrate is sample rate × bit depth × channels, so 44.1 kHz 16-bit stereo runs at 1411.2 kbps and fills about 10.58 MB per minute.

About this tool

Podcasters checking an upload limit, sound engineers sizing a session drive and developers budgeting app assets all need the same number: how many bytes a stretch of audio occupies. Pick compressed audio and enter the bitrate, or pick uncompressed PCM and choose the sample rate, bit depth and channel count, then set the length in hours, minutes and seconds. The result shows megabytes in decimal units, mebibytes as Windows and many file managers report them, gigabytes, the exact byte count, the bitrate and the storage used per minute. For compressed formats the answer assumes a constant bitrate; variable-bitrate files land near the average but can drift a few percent either way, and container headers, metadata tags and embedded artwork add a little on top.

How to use it

  1. Choose the audio type

    Compressed covers MP3, AAC, Opus and similar codecs; Uncompressed PCM covers WAV and AIFF.

  2. Set the format details

    Enter the bitrate in kbps, or pick sample rate and bit depth and use the − / + buttons for channels.

  3. Enter the length

    Fill in hours, minutes and seconds; empty boxes count as zero.

  4. Read the sizes

    Compare MB and MiB, and use MB per minute to scale to other lengths.

Examples

One minute of CD-quality WAV

Audio type
Uncompressed PCM
Sample rate
44.1 kHz (CD)
Bit depth
16-bit
Channels
2
Hours
0
Minutes
1
Seconds
0

Result File size (MB): 10.58
Size in MiB (binary): 10.09
Size in GB: 0.011
Bytes: 10,584,000
Bitrate (kbps): 1,411.2
MB per minute: 10.58

  1. Bitrate = 44.1 kHz × 16 bit × 2 ch = 1411.2 kbps
  2. Duration = 0 h × 3600 + 1 min × 60 + 0 s = 60 s
  3. Size = 1411.2 × 1000 × 60 ÷ 8 = 10584000 bytes
  4. = 10.58 MB (÷ 1,000,000) or 10.09 MiB (÷ 1,048,576)

44.1 kHz, 16-bit stereo runs at 1411.2 kbps, so each minute of uncompressed CD audio takes about 10.58 MB.

Four-minute MP3 at 128 kbps

Audio type
Compressed (bitrate)
Bitrate
128
Hours
0
Minutes
4
Seconds
0

Result File size (MB): 3.84
Size in MiB (binary): 3.66
Size in GB: 0.004
Bytes: 3,840,000
Bitrate (kbps): 128
MB per minute: 0.96

  1. Bitrate = 128 kbps
  2. Duration = 0 h × 3600 + 4 min × 60 + 0 s = 240 s
  3. Size = 128 × 1000 × 240 ÷ 8 = 3840000 bytes
  4. = 3.84 MB (÷ 1,000,000) or 3.66 MiB (÷ 1,048,576)

128,000 bits per second for 240 seconds is 3,840,000 bytes, before ID3 tags and cover art.

One hour at 320 kbps

Audio type
Compressed (bitrate)
Bitrate
320
Hours
1
Minutes
0
Seconds
0

Result File size (MB): 144
Size in MiB (binary): 137.33
Size in GB: 0.144
Bytes: 144,000,000
Bitrate (kbps): 320
MB per minute: 2.4

  1. Bitrate = 320 kbps
  2. Duration = 1 h × 3600 + 0 min × 60 + 0 s = 3600 s
  3. Size = 320 × 1000 × 3600 ÷ 8 = 144000000 bytes
  4. = 144 MB (÷ 1,000,000) or 137.33 MiB (÷ 1,048,576)

A long recording at the highest common MP3 bitrate reaches 144 MB, about 137.33 MiB as an operating system reports it.

How it is calculated

Size (bytes) = bitrate (kbps) × 1000 × duration (s) ÷ 8; PCM bitrate (kbps) = sample rate (kHz) × bit depth × channels

bitrate
Data rate in kilobits per second, where 1 kbps is 1000 bits per second
duration
Total length, counted as seconds
sample rate
Samples taken per second per channel, in kHz
bit depth
Bits stored per sample
channels
Number of audio channels, 2 for stereo

Bitrate is bits per second, so multiplying by the duration gives total bits and dividing by 8 gives bytes. Uncompressed PCM has a fixed bitrate set by its sampling: every channel stores one sample of the chosen bit depth each sample period. MB divides bytes by 1,000,000; MiB divides by 1,048,576, which is why a file manager shows a smaller figure for the same file.

When not to use it

  • Do not use it to size lossless FLAC or ALAC, whose compression ratio depends on the material.
  • It does not model video files, where the video stream dominates the size.
  • Variable-bitrate encodes only match if you enter their true average bitrate.

Common mistakes

  • Confusing kilobits with kilobytes: 128 kbps is 16 kilobytes per second, not 128.
  • Comparing a MB figure with a file manager that reports MiB and seeing a 5 percent gap.
  • Forgetting that a stereo WAV holds two channels and doubles the mono size.
  • Entering a sample rate in Hz as if it were kHz.

Frequently asked questions

How big is an hour of CD-quality WAV audio?

At 44.1 kHz, 16-bit, stereo the bitrate is 1411.2 kbps, which is 176,400 bytes per second. Over 3,600 seconds that is 635,040,000 bytes, about 635 MB or 605.62 MiB. A full 74-minute CD holds roughly 783 MB of audio.

Why does my computer show a smaller number than this result?

Windows and many tools divide by 1,048,576 and still label the result MB, though strictly it is MiB. The stats show both figures, so a 3.84 MB file appears as about 3.66 in those programs.

Does a variable-bitrate MP3 follow the same formula?

Yes, if you enter the average bitrate. A V0 MP3 typically averages around 220 to 260 kbps depending on the music, so a quiet track ends up smaller than a dense one at the same setting.

How much does 24-bit recording add over 16-bit?

Size scales linearly with bit depth, so 24-bit files are 1.5 times the size of 16-bit at the same sample rate and channel count. A 48 kHz 24-bit stereo track uses 2304 kbps, or 17.28 MB per minute.

Why is the real MP3 a little bigger than the estimate?

The formula counts only audio data. ID3 tags, embedded album art and frame headers add overhead; a 500 KB cover image alone can grow a 3.84 MB song by more than ten percent.

What bitrate should I assume for voice recordings?

Spoken-word podcasts are commonly published at 64 to 128 kbps MP3, often mono at the low end. At 96 kbps one hour comes to 43.2 MB, which fits most podcast host upload limits comfortably.

Cite this tool

Using this tool in an assignment, article or report? Copy a citation, or a link for your website.

APA

Tools Directory Editorial Team. (2026, October 24). Audio File Size Calculator. Tools Directory. Retrieved October 26, 2026, from https://tools.milunir.com/video-audio/media-utilities/audio-file-size-calculator/

MLA

Tools Directory Editorial Team. “Audio File Size Calculator.” Tools Directory, 24 Oct. 2026, https://tools.milunir.com/video-audio/media-utilities/audio-file-size-calculator/. Accessed 26 Oct. 2026.

Chicago

Tools Directory Editorial Team. “Audio File Size Calculator.” Tools Directory. Last modified October 24, 2026. Accessed October 26, 2026. https://tools.milunir.com/video-audio/media-utilities/audio-file-size-calculator/.

Link<a href="https://tools.milunir.com/video-audio/media-utilities/audio-file-size-calculator/">Audio File Size Calculator – Tools Directory</a>