Audio Converter

What this audio converter reads and what it writes

Think of the converter as a funnel with a wide mouth and two exits. The wide mouth is the list of things it can open: MP3, WAV, M4A and AAC, OGG and Opus, FLAC, and in many cases the audio track of an MP4 or WebM video. The rule is simple. If your browser can decode a file, the converter can work with it. Most current browsers handle all of the formats above, though a rare codec inside an unusual container may be refused.

The two exits are MP3 and WAV, and nothing else. The tool does not write OGG, FLAC, M4A or AAC files. That matters if you came here wanting an OGG or FLAC as the result, because you will not get one. It is better to know this before you spend time on a file than to discover it at the download button.

Why only two outputs? MP3 is the format nearly every phone, car, player, editor and upload form accepts, and WAV is the plain, uncompressed format that editors and hardware samplers accept. Between them they cover most of the situations where somebody says a file will not open.

Converting OGG, FLAC and M4A to MP3

OGG to MP3 is the most common request, and it usually comes from games, voice chat exports and some Android recorders. Drop the OGG file in, leave the output on MP3, and choose 192 kbps for speech or 256 to 320 kbps for music. The page decodes the Vorbis or Opus audio and then encodes it again as MP3. Because both formats throw away detail to save space, the second encode costs a little extra, so pick a generous bitrate and avoid converting back and forth.

FLAC to MP3 is a different story. FLAC keeps every sample of the original, so you are making a single lossy copy from a perfect source, which is the best case for MP3. At 320 kbps many listeners cannot separate the result from the FLAC on ordinary headphones, and the file lands at roughly a quarter of the size of a WAV, which helps when a phone is nearly full.

M4A files from iPhone voice memos and from many music stores convert the same way. If a particular M4A is protected by copy protection, the browser cannot decode it, and the page reports that the file could not be read. This tool works only with files you already have and are entitled to use. It does not download audio from streaming sites or web addresses, and it does not remove protection.

Audio from video files

Plenty of people want only the sound from a clip they recorded: a lecture on their phone, a band rehearsal filmed from the back of the room, a screen recording with narration. The converter often reads the audio track of MP4, MOV and WebM files directly, so you can drop the video in and save the sound as MP3.

Expect it to take longer than a pure audio file, because the whole video has to be read, and files can be as large as 250 MB. If the page cannot decode a particular video, the cause is usually a codec the browser does not include. Opening the clip in a media player and exporting the audio there is a workable detour.

As with every file on this page, the clip has to be yours or be something you have permission to use. The tool has no function that fetches video from the web.

Choosing a bitrate

Bitrate is the amount of data used per second of sound, counted in kilobits per second, and for MP3 it sets the file size almost exactly. A minute at 128 kbps is about 1 MB, with 192 kbps near 1.4 MB and 320 kbps near 2.4 MB. The table in the Numbers tab shows the same arithmetic next to uncompressed WAV so you can see how much each choice costs.

For the question of a good bitrate for streaming or sharing, there is no single answer, but there are sensible zones. Spoken word such as podcasts, lectures and voice memos sounds fine at 128 kbps, the lowest this tool offers, especially in mono. Everyday music for phones and earbuds is comfortable at 192 kbps. If the file might be played on a good sound system, or edited later, 256 to 320 kbps leaves room.

The best bitrate for MP3 files that you intend to keep is the highest one the tool offers, 320 kbps, because storage is cheap and you cannot get lost detail back later. The best one for something you will send over a messaging app with a size limit is the lowest that still sounds right, and the only way to find out is to listen. Convert a short passage, play the Result against the Original, and move up one step if you hear a swishy, watery texture around cymbals or in the quiet tails of notes.

Sample rate and channels

Two more options sit beside the format. Sample rate can stay as it is or be set to 44.1 kHz, 48 kHz or 22.05 kHz. Keeping the original is the right choice most of the time. Choose 44.1 kHz for music that will be burned or shared widely, 48 kHz when the file belongs with video, and 22.05 kHz for speech, when a smaller file matters more than the highest octave.

Channels can stay as they are, become stereo, or be folded to mono. Mono halves the data of a WAV, and for an MP3 it lets the bitrate go further, because all of it goes to one signal. A single-microphone interview is the classic case: it was never stereo, so a stereo file only repeats the same signal twice.

Folding a stereo music mix to mono can change its character, because anything that was out of phase between the sides cancels. Listen to the result before you keep it.

Is FLAC better than WAV?

Both are lossless. They hold the same audio, sample for sample, so neither sounds better. The difference is storage: FLAC compresses the data without loss and usually takes about half the space of the matching WAV, and it carries tags such as artist and title more neatly. WAV is simpler and is accepted by nearly every editor, sampler and broadcast system.

For this page, the practical point is that FLAC is something it reads but does not write. If your goal is a smaller, fully lossless archive, you need a tool that saves FLAC. If your goal is a file that every device opens, convert the FLAC to MP3, or to WAV when an editor demands it.

Fidelity only drops at the step that is lossy. A FLAC converted to WAV loses nothing. A FLAC converted to MP3 loses a little by design, and the 320 kbps setting keeps that loss small.

Common mistakes and quick checks

The most common mistake is converting an MP3 to WAV and expecting better quality. The WAV will be larger, but it will sound exactly like the MP3, because the detail removed by the first encode is gone for good. The page on MP3 to WAV covers that in depth.

A second mistake is repeated lossy conversion: MP3 to OGG to MP3 to another bitrate. Each pass adds a small error, and the errors accumulate into a dull, smeared sound. Keep the best source you have, and make each export from that source.

Before you save, use Result and Original to compare at the same point in the track, and glance at the estimate. If the estimate is far above what you expected, check whether the output is set to WAV at 24 bit, which is the large option. If the file seems too quiet or too loud afterwards, the converter did not change the level; that is a job for the loudness tools instead.

Once you are done, the links under the tool carry the converted result into the next step, such as trimming or normalizing, without a second upload because nothing was uploaded in the first place.

Privacy and large files

Decoding and encoding both happen inside your browser tab, using your own processor. The audio never travels to a server, which is handy for unreleased songs, client recordings and anything with a private conversation in it. The last file you opened is kept in this browser's storage on this device so the next tool can offer to continue with it; clearing site data removes it.

The input limit is 250 MB per file. A one-hour recording as WAV is large and takes time to process on a slow phone, so on weaker devices it can help to close other tabs while the conversion runs.