Free converters · Run in your browser
Free audio converters
Short answer
50 audio converters, free and with no upload. Going from WAV to MP3 made a 1.92 MB file 161 KB (-91.6%) in 0.23 seconds natively and 0.10 s in the browser engine on a 3 second clip; the other direction cannot bring the sound back, only make a bigger file.
Measured audio conversions
Every audio converter
50 pairs. Each page has a working converter, the facts about both formats and, where we measured it, what the conversion does to the size.
M4A to FLAC
M4A to Opus
MP3 to Opus
WAV to Opus
AAC to Opus
Opus to OGG
OGG to Opus
FLAC to Opus
Opus to FLAC
MP3 to WAV
WAV to MP3
MP3 to AAC
AAC to MP3
MP3 to OGG
OGG to MP3
MP3 to FLAC
FLAC to MP3
MP3 to M4A
M4A to MP3
WAV to AAC
AAC to WAV
WAV to OGG
OGG to WAV
WAV to FLAC
FLAC to WAV
WAV to M4A
M4A to WAV
AAC to OGG
OGG to AAC
AAC to FLAC
FLAC to AAC
AAC to M4A
M4A to AAC
OGG to FLAC
FLAC to OGG
OGG to M4A
M4A to OGG
FLAC to M4A
Opus to MP3
Opus to WAV
Opus to AAC
Opus to M4A
AIFF to MP3
AIFF to WAV
AIFF to AAC
AIFF to M4A
WMA to MP3
WMA to WAV
WMA to AAC
WMA to M4A
Key takeaways
- The MP3 is written at about 128 kbps: in our tests a 10 second clip gave 161 KB whatever it came from (161 KB, 161 KB, 161 KB, 161 KB, 161 KB).
- Extracting is fast because no picture is decoded: 0.26 s, 0.29 s, 0.33 s natively, 0.10 s in the browser engine.
- A lossless target cannot restore anything: MOV to WAV made 1.92 MB from the same 10 seconds, 11.9 times the MP3, with the same sound as the video's AAC track.
- Converting a lossy file to another lossy format costs a little quality: M4A to MP3 is one more lossy step, and its file was 161 KB against 243 KB.
- Everything runs in your browser: nothing is uploaded, and there is no account.
Measured: what each conversion does
In your browser the converters run ffmpeg compiled to WebAssembly on one thread, so re-encoding is far slower than on a desktop. The first conversion downloads the engine, about 30 MB, once per visit. Native timings are from ffmpeg 6.1.1 on a server with a 10 second 1080p clip; WebAssembly timings are from the shipped core on a 3 second clip, in a headless run.
| Conversion | Input | Output | Change | Native time | WebAssembly time |
|---|---|---|---|---|---|
| WAV to MP3 | 1.92 MB | 161 KB | -91.6% | 0.23 s | 0.10 s |
| M4A to MP3 | 243 KB | 161 KB | -33.7% | 0.25 s | 0.10 s |
| FLAC to MP3 | 1.25 MB | 161 KB | -87.1% | 0.22 s | not measured |
| WAV to M4A | 1.92 MB | 163 KB | -91.5% | 0.43 s | 0.20 s |
Size and time of the audio conversions we measured on the same 10 second clip.
All of these are audio re-encodes, so they take a fraction of a second on a short clip; time grows with the length of the recording.
Which audio format?
| Format | Compression | Best for |
|---|---|---|
| MP3 | Lossy | Music and podcasts that must play on every device |
| WAV | Uncompressed | Editing and mastering, where every sample matters; very large files |
| M4A | Lossy or lossless | Apple devices and voice memos |
| FLAC | Lossless | Archiving music at full quality in less space than WAV |
Limits to know about
- Files up to 100 MB; the first conversion downloads about 30 MB of engine.
- A conversion to a lossy format costs some quality, how much depends on the clip and the quality setting; keep the original.
- A conversion to a lossless format (WAV, FLAC) makes a bigger file and cannot restore quality that was already lost.
Questions people ask
How do I extract the audio from a video?
Use one of the video to audio converters, for example MP4 to MP3. The picture is dropped and the sound is saved in the format you chose.
What MP3 quality does it write?
About 128 kbps. A 10 second clip gave 161 KB.
Does it work on a phone?
Yes, in the browser. The engine downloads once per visit.
Is my file uploaded?
No. Every conversion runs in your browser.
Can I get a WAV from an MP3?
You can convert it, but the file only gets bigger: the quality the MP3 discarded does not come back.
What is the size limit?
Up to 100 MB per file.
Sources and how we checked
- FFmpeg Documentation: ffmpeg (stream selection, -map, -c copy) (read 2026-10-08)
- MDN: Media container formats (read 2026-10-08)
- Blender Foundation: Big Buck Bunny (CC BY 3.0), the clip used for the video and audio measurements (read 2026-10-08)
Reviewed October 9, 2026. Every figure on this page comes from the measurements behind the linked tool pages, which are saved in data/seo/hub/evidence/2026-10-09.