Which format is best for speech?

Opus at 32–48 kbps sounds excellent and is tiny, but needs Opus support; MP3 at 64–96 kbps mono is the compatible choice.

Can I convert lossy to lossless?

Yes, but it does not restore lost quality; it only prevents further loss in editing.

Only when a codec cannot be handled in the browser (for example AAC encoding in Firefox). The page tells you before uploading.

Audio Converters

Audio Converter

One page for every audio job: pick the output format, bitrate, sample rate and mono/stereo, drop any number of files and download a ZIP.

Runs in your browser — files never leave your device.

Drop supported files here

or click to browse · paste from clipboard · up to 2000 MB each

Select files

Options

Convert to

Bitrate

Sample rate

Channels

About Audio Converter

Dedicated pairs (WAV to MP3, M4A to MP3) cover the common cases; this converter handles the rest — FLAC to WAV for a DAW, MP3 to OGG for a game engine, anything to Opus for voice — and lets you set technical parameters explicitly.

Decoding uses the browser’s media stack (MP3, WAV, FLAC, OGG/Opus, AAC and the audio of MP4/MOV/WebM/MKV videos); encoding uses a WebAssembly MP3 encoder and the browser’s own Opus, AAC and PCM encoders. FLAC is accepted as input; lossless output is written as WAV.

How it works

Drop your files onto the box above, click it to browse, or paste from the clipboard.
Adjust the options if you need to — the defaults suit most cases.
Press Convert. The work happens on your device, so speed depends on your computer or phone.
Download the result — individually or all at once.

About the formats

MP3 · MPEG-1 Audio Layer III · .mp3

The audio format everything can play: cars, phones, old players, websites. Lossy, but at 192–320 kbps close to indistinguishable from CD.

All MP3 patents expired in 2017; the format is now free to use.
128 kbps is the classic “good enough” rate; 320 kbps is the maximum.
MP3 cannot store multichannel surround or lossless audio.

WAV · Waveform Audio · .wav

Uncompressed PCM audio, the studio and archival standard: perfect quality, about 10 MB per minute at CD quality.

WAV is a container; almost all WAVs hold uncompressed 16- or 24-bit PCM.
A 4 GB file-size limit applies to standard WAV; long recordings use RF64 or BWF.
Because nothing is compressed, converting WAV to MP3 is the fastest way to shrink audio 10×.

M4A · MPEG-4 audio (AAC) · .m4a

Apple’s audio format from iTunes, Voice Memos and the Music app: AAC audio in an MP4 container, better than MP3 at the same bitrate.

M4A usually holds AAC; the .m4a from Apple Music purchases may be ALAC (lossless) instead.
Voice Memos on iPhone save M4A; many transcription and Android apps prefer MP3.
M4A supports chapters and cover art metadata.

AAC · Advanced Audio Coding · .aac

The successor to MP3 used by YouTube, Apple and broadcast: more efficient compression, usually wrapped in M4A or MP4.

A raw .aac file is an ADTS stream without a proper container, so some players cannot seek in it.
AAC at 128 kbps sounds roughly like MP3 at 160–192 kbps.
AAC is the mandatory audio codec in MP4 video.

Related conversions

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