Audio File Size Calculator
Estimate the approximate size of an encoded audio file from duration and average audio bitrate. The result is useful for podcast exports, music files and storage planning.
How to use this calculator
- Enter audio duration in minutes and the encoded average bitrate in kilobits per second.
- Check the labels and units before applying the result to a real task.
- Change one input at a time when comparing scenarios.
Formula and method
File bytes ≈ duration seconds × bitrate bits/s ÷ 8
- File bytes ≈ duration seconds × bitrate bits/s ÷ 8
- Variable bitrate, metadata, multiple channels/tracks, container overhead and padding can alter the final file size.
Worked examples
Worked example
A 60-minute audio file encoded at an average 128 kbps.
3,600 seconds × 128,000 bits/s ÷ 8 ≈ 57.6 MB in decimal units.
3,600 seconds × 128,000 bits/s ÷ 8 ≈ 57.6 MB in decimal units.
Understanding the result
Estimate the approximate size of an encoded audio file from duration and average audio bitrate. The result is useful for podcast exports, music files and storage planning.
Variable bitrate, metadata, multiple channels/tracks, container overhead and padding can alter the final file size.
Important notes
Variable bitrate, metadata, multiple channels/tracks, container overhead and padding can alter the final file size.
Displayed values are rounded for readability; retain appropriate precision when continuing a calculation.
Frequently asked questions
Does stereo automatically double the estimate?
Not when the entered bitrate already represents the total encoded stream. Use the encoder’s total bitrate rather than a per-channel rate.
Does this estimate uncompressed WAV audio?
It estimates from a supplied encoded bitrate. For uncompressed PCM, calculate from sample rate, bit depth, channels and duration instead.
Why can the finished file be a little larger?
Container headers, metadata, tags, padding and encoder behaviour can add data not represented by the average audio bitrate alone.
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Related explanations
Learn the method behind the number or compare the terminology before using the calculator.
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This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.