Audio tools
Convert, trim, join, and shrink audio, and pull the sound out of a video.
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Most popular
All audio tools
Turn a large uncompressed recording into a file you can actually send.
Convert voice memos and iTunes audio for players that only read MP3.
Shrink a lossless library down for a phone or a car stereo.
Lower the bitrate to make an audio file smaller.
Keep the parts you want or cut sections out, saved as one file or one per section.
Join two or more recordings into one file, in the order you choose.
Pull the soundtrack out of a video, with or without re-encoding it.
About these tools
These tools run on the audio codecs already built into your browser, driven by a decoder that reads the container — the MP4, WAV, or FLAC wrapper — and hands the compressed packets to the browser to decode. MP3 is the one thing no browser can write, so a small WebAssembly build of the LAME encoder loads the first time you convert something. Nothing else is downloaded, and nothing is uploaded: the counter under each tool watches the network while your file is processed and stays at zero bytes sent.
Which codecs your browser can read is not a fixed list, so these pages check rather than assume. Chrome, Edge, and Safari cover everything here. Firefox depends on the codecs your operating system provides and commonly ships without AAC, which is what M4A files contain — if that is your situation, the tool says so by name instead of failing with a shrug halfway through.
Every conversion on this page loses something, and each tool says what. Going from WAV or FLAC to MP3 trades detail for size, which is usually the point. Going from M4A to MP3 costs a generation of quality without gaining any, and is only worth doing for a device that cannot play the original. Cutting and joining both re-encode, because finding an arbitrary point in a compressed stream — or putting two streams on one timeline — means decoding first. The one genuinely free operation here is extracting an existing audio track out of a video, which copies the packets across untouched.
For anything you are keeping rather than sending, remember which direction is one-way. A lossy file can always be made smaller and never made better: re-encoding a 128 kbps MP3 at 320 kbps produces a file two and a half times the size containing the same audio, slightly worse.
FAQ
Are my files uploaded to a server?
No. Every tool here decodes and encodes in your browser, and the network counter under each one monitors activity while your file is processed and stays at zero bytes sent. The only download is the MP3 encoder itself, which loads before processing starts.
Why does the first conversion take a moment to start?
The MP3 encoder is a WebAssembly module that downloads once per session, because no browser can write MP3 on its own. It is fetched before your file is touched, so it never counts against the network readout, and subsequent conversions start immediately.
Which formats can I convert from?
WAV, MP3, M4A, AAC, FLAC, OGG, and Opus for audio, plus MP4, MOV, WebM, and MKV for video files you want the sound out of. AIFF, AVI, and WMA are not among them — no browser can read those containers, so they are refused by name rather than half-processed. Beyond the container, what your browser can actually decode is checked per file, and you are told if a codec is missing.
Is there a size limit?
None is imposed, and since nothing is uploaded there is no server limit to hit — the ceiling is your own tab's memory. Files are read off disk a few megabytes at a time rather than loaded whole, so what is held is the file being written, not the one you gave. Measured here: a 747 MB WAV converted in about 21 seconds, and a 2.3 GB video gave up its audio in about one. The single exception is the merge tool, which has to decode a whole file into memory when its sample rate or channel count needs matching to the others.
Can I convert an MP3 to WAV to improve it?
You can convert it, but it will not improve anything. The detail MP3 discards is not stored anywhere in the file, so the WAV is simply a much larger container holding the same audio. Converting up is only useful when a specific piece of software refuses to read the compressed format.