Audio Converter: Free Online MP3, WAV, AAC & FLAC Converter, No Upload

Free Online Audio Converter — 100% Local, No Upload

This converter uses FFmpeg compiled to WebAssembly, running entirely in your browser tab. Your audio files never leave your device. Drop in a file, pick MP3, AAC, OGG, OPUS, FLAC, or WAV as your target, and convert one file at a time or a whole batch at once. Video files work too: the converter strips out the video track and exports whatever audio is inside.

Choosing the right output format

MP3 remains the safest choice when you need a file that plays on anything, from a decade-old car stereo to any phone or laptop made in the last twenty years. AAC, the format Apple standardized on, delivers noticeably better quality than MP3 at the same bitrate and works natively across iOS and most modern platforms. OGG uses the open-source Vorbis codec and compresses efficiently for its size, a natural fit for web audio and open pipelines. OPUS pushes that further, holding up quality at bitrates where MP3 and AAC both start to fall apart, which makes it the strongest option for bandwidth-constrained streaming or voice. FLAC and WAV sit apart from the other four: both are lossless, so no bitrate setting applies. FLAC compresses that lossless data down to roughly half the size of WAV without losing anything, while WAV stores audio completely uncompressed, at around 10 MB per minute for CD-quality stereo.

Extracting audio from video

Drop an MP4, MOV, MKV, or WebM file into the same drop zone you would use for an audio file, and the converter recognizes it, strips the video stream, and hands you the audio track in whichever format you selected. This works for pulling a podcast-style track out of a screen recording, grabbing music from a downloaded video, or archiving just the audio commentary from a longer clip without keeping the full video file around.

Picking a bitrate

For any lossy output format, a bitrate selector appears with four presets: 96 kbps for low-priority background audio, 128 kbps as a solid standard for casual listening, 192 kbps as the sweet spot most people settle on for music, and 320 kbps as the practical ceiling for lossy encoding, where further increases stop producing an audible difference for almost anyone. Higher bitrates mean larger files in exchange for more preserved detail, so match the setting to what the audio needs rather than defaulting to the maximum every time.

Avoiding quality loss

Converting between two lossy formats, MP3 to AAC for instance, re-encodes audio that has already been compressed once, which bakes the first round of artifacts into the second. If you have access to a FLAC or WAV version of the source, convert from that instead of from an existing MP3, and you will end up with a cleaner result no matter which lossy format you land on. When quality is not a concern, such as converting a voice memo for compatibility, this generational loss matters far less and any source file will do.

Single files and batch conversion

The Single tab is built for one-off conversions and shows a live audio preview of the result before you download it. The Batch tab applies one format and bitrate to every file you drop in, then works through the queue file by file, which is the faster path when you are converting a whole folder of recordings or an album at once rather than repeating the same steps over and over.

Common use cases

Musicians convert WAV masters down to MP3 or AAC for sharing with collaborators who do not need the full-resolution file. Podcasters standardize a batch of episodes recorded in different formats down to a single consistent MP3 or AAC output before publishing. Developers pull FLAC into WAV when a project pipeline expects uncompressed audio. Anyone dealing with a file that a specific app or device refuses to play usually just needs the right container and codec, which is what this tool solves in a couple of clicks rather than a full audio editing suite.

How the conversion runs

The FFmpeg engine, about 32 MB, downloads once and your browser caches it, so only the first conversion in a session pays that cost. After that, every file you drop in gets decoded and re-encoded on your own machine using your CPU, not a remote server, which is why nothing needs to leave your device in the first place. Larger files and higher target bitrates take longer to process since there is more audio data to encode, and a progress indicator tracks the job so you can see it is still working. Once the output appears you get an inline audio preview to confirm it sounds right before downloading.

Related: Audio Compressor to reduce file size, or Video to Audio for dedicated video audio extraction.

Frequently Asked Questions