Audio file-size estimator
Estimate an audio file's approximate size from its bitrate and duration before exporting or downloading; the result excludes some encoding and file overhead.
Result
Estimated file size
How to use this tool
- Enter the audio bitrate — 128kbps is common for smaller files, 192–320kbps for higher quality.
- Enter the track or recording's duration in minutes.
- Read the estimated file size.
Assumptions
- Assumes a constant bitrate — variable-bitrate encoding will give a somewhat different actual size.
- Doesn't account for file format overhead such as metadata, album art, or container details, which adds to the encoded audio data.
Technical details: what the fields mean
- Audio bitrate
bitrateKbps - Audio bitrate — 128kbps is a common 'good enough' quality, 320kbps is near the top of typical MP3 quality.
- Duration
durationMinutes - Total length of the audio.
Methodology
Estimated audio data size (decimal MB) = bitrate (kbps) × duration (seconds) ÷ 8 ÷ 1000. This estimates the encoded audio stream, not every byte in the finished file.
Worked example
192kbps, 4-minute track
Inputs: Audio bitrate: 192 kbps, Duration: 4 minutes
Result: 5.76 MB
Practical guidance
- For podcasts and spoken-word content, a lower bitrate (96–128kbps) is usually indistinguishable from higher bitrates and keeps files smaller.
Common mistakes
- Assuming all audio formats at the same bitrate produce the same file size — different codecs and encoding methods have different efficiency.
FAQs
How big is a 4-minute song at 192kbps?
About 5.76MB — enter your own bitrate and duration above for an exact estimate.
Last reviewed: 2026-10-11
Assumes a constant bitrate and estimates the audio stream only; variable-bitrate encoding and file overhead such as metadata or embedded artwork can change the finished file size.
This tool provides an indicative estimate, based on the assumptions stated above.
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