hi,i dragged an mp3 to audacity,the mp3 is a 4 hour dj mix 350 mb,i noticed the time remaining was around 10 mins i thought was strange,left and came back and got couldnt copy storage full!
i had 8 gb left on hdd before copying started,now down to 8kb
where did the file go to on my pc? i wantto delete it to free up space.
thanks its ok i closed audacity and back up to 8gb storage remaining.
but why was it taking up so much storage to import the file to audacity?

 

Audacity has to convert the MP3 before it can edit it! Also, you can set it to 16-bit instead of 32-bit.

Edit > Preferences > Quality

Conversion
These options concern the trade-offs that arise when converting from one sample rate to another and one sample format to another.

For example, sample rate conversion is necessary whenever the sample rate of the track does not match the current Project Sample Rate. Sample format conversion would be required upon export if you used the default 32-bit float sample format but exported a 16-bit audio file.

Sample rate conversion is also performed when using a Time Track so that the speed-changed audio can retain its current sample rate. However for Time Track resampling Audacity automatically selects a quality level tailored for this purpose and so changing the converter qualities below will not affect Time Tracks.

• Real-time and High-quality: Both the Sample Rate Converter and the Dither (for conversion between sample formats) have options for use in different circumstances.
  • The "Real-time" options are only used when converting sample rates or formats for playback in Audacity.
  • The "High-quality" options are used for sound that is being converted for storage on disk, for example when rendering or exporting audio.
• https://manual.audacityteam.org/man/quality_preferences.html

 

Last edited: Jun 12, 2026 at 3:20 PM

The math is relatively simple: Expansion Ratio ≈ PCM Bitrate ÷ Average MP3 Bitrate. It's float + temporary storage.

But the numbers question which should be more important to you, is what the hell you are using a hdd or SSD with only 8gb free space on it for to begin with.

 

Maybe you ran out of RAM and it started swapping to disk.

Decoding 4 hours of music => 4h * 60 minutes * 60 seconds * 48000 samples per second * 2 channels (stereo) * 8 bytes per double precision sample ~= 10 GiB of RAM, and that's just the file and nothing else.