Audacity's WAV and AIFF exports stop at 4GB, and the manual is careful to say the rule is not Audacity's own: "WAV and AIFF files are limited to a maximum size of 4GB (this is a general restriction and not an Audacity one)."
What 4GB buys you in recording time is not a single number. It depends on bit depth and channel count, and the Audacity Manual publishes the exact arithmetic. It also buries a second, much lower ceiling in a footnote — the one that actually ruins people's day.
The limits, at a glance
These are the manual's own figures, from its table titled "Maximum sizes for files in time duration (hours:minutes)":
| Sample format | Stereo | Mono |
|---|---|---|
| 16-bit (default) | 6h:45m | 13h:31m |
| 24-bit | 4h:30m | 9h:01m |
| 32-bit | 3h:22m | 6h:45m |
Two things to read carefully before you plan a session around these.
First, the manual flags them as ceilings, not targets: "These timings are the theoretical maximum times. You would be well-advised to restrict yourself to slightly lower limits to afford some head-room."
Second, the per-minute cost. Audacity's format comparison table lists WAV 16-bit PCM at 5.0 MB per minute mono and 10.0 MB per minute stereo, measured "at default Audacity settings (that is, 44,100 Hz sample rate and default bit rate or quality settings in the case of compressed formats)". That is the number to multiply if your project rate is not the default.
The 2GB wall nobody mentions
Footnote (1) on that same table is the most important sentence on the page, and competitor write-ups routinely skip it:
"The practical file size limit is 2 GB in many player applications due to their interpretation of the file size header. This also applies to 24-bit and 32-bit files where those bit depths are valid."
Read the qualifier: 2 GB is a limit "in many player applications", not a limit in Audacity. Audacity's own trap only fires above 4GB, so a 3.5GB export goes through. Whether the app on the other end can open it is a separate question, decided by how that app interprets the file size header.
The practical consequence is that the table above has a shadow version at roughly half the durations if the file has to survive a trip into another program. If you are handing a long recording to someone else, that is the number to plan against, not 4GB.
Why Audacity refuses before it even starts
Uncompressed audio is the one case where the finished size is knowable in advance, and Audacity uses that. From the manual's page on unsuitable drives: "WAV and AIFF files are always subject to a maximum 4GB limit (and the forecasted size can be accurately calculated in advance, unlike with compressed file formats)." Because of that, "Audacity therefore has a special trap for this case and does not even attempt to make the export".
So an over-4GB WAV export fails immediately rather than grinding for twenty minutes and dying at the end. That is deliberate, and it is why the error arrives before any progress bar does.
What to do when you hit it
In rough order of how little you give up:
- Export FLAC instead. It is still lossless, and the manual puts its output at "about half as large as the uncompressed WAV or AIFF formats, but larger than compressed, lossy formats" — 2.5 MB per minute mono, 5.0 MB per minute stereo at 16-bit.
- Check your export bit depth. The WAV export default is "Signed 16-bit PCM, which is CD quality". If you are exporting 32-bit, you are spending your 4GB twice as fast for a delivery file.
- Export mono if the content is mono. The table doubles your ceiling for a single-channel export.
- Use RF64 or CAF for genuinely huge files. This is the official answer, and it is exact.
For step 4, the manual's page on other uncompressed formats says: "RAW, RF64 or CAF (Apple's Core Audio Format) headers (with PCM encoding in all three cases) may be used if extremely large files similar to WAV or AIFF are required. The RF64 and CAF size limit is about 16 exabytes (effectively unlimited, as there are no disks of that size), making it suitable for very long multi-channel files."
You reach it through File > Export Audio, then choosing Other uncompressed files from the Format dropdown. Note the default in that dialog is not RF64: it "defaults to WAV (Microsoft) signed 16-bit PCM on Windows and Linux and to AIFF (Apple/SGI) signed 16-bit PCM on Mac", so you have to change the header yourself. The manual gives the size limit for RF64 and CAF but does not cover which players can read them — check the official documentation before you commit a long archive to one.
If the long recording you are about to open in Audacity is currently a video file, pull the audio out first rather than importing the whole thing:
Try it right here
Runs in your browser. Your file is not uploaded anywhere.
This runs in your browser tab — the file is decoded locally and never uploaded. It hands back a lossless WAV, so the same duration table applies to what comes out: multiply the minutes by 10.0 MB for stereo before you assume it will fit.
Platform-specific gotchas
FAT and FAT32 drives put the same 4GB wall around everything. The manual states it directly: "FAT and FAT32 formatted drives are subject to a 4GB limit for any single file, this makes them unsuitable for use in Audacity for live projects." Exports are allowed there — "FAT/FAT32 drives can readily be used for Exports of audio files from Audacity" — but "the 4GB limit also applies to such exports". When that export fails, "freeing up space will not work and you will need to Export to a non-FAT formatted drive", and clicking OK on the error "will remove the partially exported file from your FAT/FAT32 drive". For projects, the manual's fix is to "reformat your USB drive as exFAT format which will accommodate much larger files".
Do not mix up the two default bit depths. The same manual page quotes both 3h:22m and 6h:45m for stereo, which looks contradictory until you notice they describe different things. The project default is 32-bit, so "about 3 hours 22 minutes of stereo at default settings" is the FAT32 ceiling for a live project. The export default is 16-bit, so "you get a maximum size of about 6 hours 45 minutes of stereo audio for WAV and AIFF at Audacity's default settings". Both lines match the table above; they just sit at opposite ends of your workflow.
Stereo is the export default even when your tracks are mono. The Export Audio dialog describes the Stereo channel setting as "the default setting even if you only have mono tracks for exporting". Leave it alone on a mono recording and you halve your maximum length for no benefit.
Compressed formats are not part of this problem. For MP3 and AAC, the manual says "the maximum size will be much larger and unlikely to be an issue for most, if not all, users". If you are exporting a deliverable rather than a master, WAV to MP3 removes the question entirely.
FAQ
What is the maximum WAV file size in Audacity? 4GB. The manual describes it as "a general restriction and not an Audacity one" — it comes from the WAV format, not the application. AIFF is subject to the same limit.
How many hours of audio fit in a 4GB WAV? At 44,100 Hz: 6h:45m stereo or 13h:31m mono at 16-bit, 4h:30m / 9h:01m at 24-bit, and 3h:22m / 6h:45m at 32-bit. Audacity calls these "the theoretical maximum times" and advises staying slightly under them.
Why won't my 3GB WAV open in another program? Possibly the second ceiling. Audacity's footnote says "the practical file size limit is 2 GB in many player applications due to their interpretation of the file size header", and that this applies at 24-bit and 32-bit too. The file is not broken; the reader is hitting its own header limit.
How do I export a file larger than 4GB from Audacity?
Choose Other uncompressed files in File > Export Audio and set the header to RF64 or CAF. The manual puts their limit at "about 16 exabytes (effectively unlimited, as there are no disks of that size)".
Does the 4GB limit apply to Audacity projects too? Not as a format limit, but a FAT/FAT32 drive imposes one on any single file, which is why the manual says such drives are "unsuitable for use in Audacity for live projects" and points to exFAT instead.
Will lowering the sample rate help? The manual's per-minute figures are quoted at 44,100 Hz, so they only hold at that rate. The pages cited here give no conversion for other rates — check the official documentation, or keep the default and use the table as written.
All figures above are quoted from the Audacity Manual, checked 16 September 2026. More size and format ceilings are collected in our limits guides; if Audacity is refusing your source file instead of your export, see why Audacity cannot import MP4. The browser-based converters are listed under all Clapr tools.
