Audio Converter — Free & Online
A free online audio converter that runs in your browser. Convert between MP3, WAV, M4A (AAC), FLAC and Opus with bitrate control — no upload, no software to install.
What is an online audio converter, and is it safe?
To convert audio, load your file, choose an output format and (for the compressed formats) a bitrate, then press Convert. MP3 is the universal choice that plays everywhere; M4A/AAC suits Apple devices; Opus gives the smallest files at good quality; and FLAC or WAV keep the audio lossless when quality matters more than size. It reads almost any input — MP3, WAV, M4A, FLAC, Opus, OGG, AIFF and more — and everything runs on your device with ffmpeg compiled to WebAssembly, so nothing is uploaded. Converting one specific pair? M4A to MP3, WAV to MP3 and FLAC to MP3 are one-click pages for the three most common conversions; use this converter for everything else. Want to cut a clip instead? Use the MP3 Trimmer, or raise a quiet recording with the Volume Booster.
MP3 vs WAV vs FLAC vs M4A vs Opus — which should you use?
Sizes are for a 3-minute stereo track at 44.1 kHz.
| Format | Compression | Typical bitrate | 3-min track | Plays on | Best for |
|---|---|---|---|---|---|
| MP3 | Lossy | 128–320 kbps | ~4.3 MB at 192 kbps | Virtually every device ever made | Sharing, car stereos, old players — the safe default |
| M4A (AAC) | Lossy | 128–256 kbps | ~2.9 MB at 128 kbps | Apple devices and most modern players | Better quality than MP3 at the same bitrate |
| Opus | Lossy | 96–160 kbps | ~2.9 MB at 128 kbps | Modern browsers and Android; not older hardware | Smallest file at a given quality; speech and streaming |
| FLAC | Lossless, compressed | ~700–1,100 kbps | ~18 MB | Most players, but not every phone or car stereo | Archiving — about 40–50% smaller than WAV, bit-identical |
| WAV | Uncompressed | 1,411 kbps (16-bit/44.1 kHz) | ~32 MB | Everything, including every DAW | Editing and mastering; by far the largest files |
The short version: keep WAV or FLAC as the master copy, and hand out MP3 when the file has to open on someone else’s device. Converting one lossy format to another re-compresses the audio a second time, so always convert from the highest-quality source you still have.
Frequently Asked Questions
Which audio formats can I convert between?
You can load almost any common audio file — MP3, WAV, M4A/AAC, FLAC, Opus, OGG, AIFF, WMA and more — and convert it to MP3, WAV, M4A (AAC), FLAC or Opus. MP3, M4A and Opus are compressed (lossy) formats with a bitrate you choose; FLAC and WAV are lossless, so they keep every detail at the cost of a larger file. Pick MP3 for maximum compatibility, M4A for Apple devices, Opus for the smallest size at good quality, and FLAC or WAV when you need lossless.
Is my audio uploaded to a server?
No — audio conversion runs entirely on your device with ffmpeg compiled to WebAssembly, so your file is never uploaded to a server, logged or stored. The engine downloads once on the first conversion (about 10 MB) and is then cached, so later runs start instantly. That makes it safe for private recordings, voice memos and music you own, and closing the tab clears everything.
Will converting reduce the quality?
Whether converting reduces quality depends on the target format. Converting to a lossless format (FLAC or WAV) preserves the audio exactly. Converting to a lossy format (MP3, M4A or Opus) re-encodes the sound and discards some detail to save space — at 192 kbps and above this is usually inaudible. Converting a lossy file to another lossy format re-compresses it a second time, so for the best result convert from the highest-quality source you have and choose a bitrate of 192 kbps or higher.
What bitrate should I choose?
The right MP3 bitrate depends on the material: 128 kbps is fine for speech and casual listening, 192 kbps is a good all-round choice, and 256 to 320 kbps is near-transparent for music. M4A (AAC) and Opus sound as good or better at the same bitrate, so you can often go a little lower with them — Opus in particular holds up well down to 96 to 128 kbps. Lossless FLAC and WAV ignore the bitrate setting because they keep the full signal.
How big can my file be?
Your audio file has no hard size limit other than your device's available memory, because the work happens locally in the browser. Short clips and songs convert in a few seconds; very long files (a full album or a multi-hour podcast) take longer and use more memory, and extremely large files can exceed what the browser tab can hold. For those, convert in sections. The engine runs on your own CPU, so a faster device converts faster.