Which formats can this audio format converter read and write?

It writes MP3, WAV, FLAC, M4A (AAC) and OGG (Opus). It reads MP3, M4A, AAC, WAV, FLAC, OGG, Opus, WebM audio, AIFF, AMR and WMA, and it will try any other audio type your browser can decode. Each conversion is one file.

Does converting to WAV or FLAC improve the quality?

No. If the source is lossy, such as an MP3, the detail it lost is gone. WAV and FLAC store what is left without losing more, in a larger file. They keep full quality only when the source was lossless to begin with.

Why are M4A or OGG greyed out, or why did my file fail?

Those two outputs use encoders built into the browser, and not every browser has them. For M4A, try Chrome on a computer. For OGG, try a current Chrome or Edge, Firefox 130 or later on a computer, or Safari 26 or later. On input, MDN lists Safari as the only browser that decodes Apple Lossless, says Firefox relies on the system for AAC, and OGG on Apple devices needs iOS 18.4 or macOS Sequoia 15.4. Damaged and copy-protected files cannot be read.

Is my audio file uploaded?

No. Decoding and encoding happen on your device, and closing the page clears the result. The site's analytics record events such as a conversion starting and the format chosen, but not the file or its name.

How large a file can I convert?

Up to 100 MB and 30 minutes, because the whole recording is held in your device's memory while it converts. A phone may struggle sooner than a computer. For a longer recording, trim or split it first.

Audio Format Converter

Pick one audio file and the format you need: MP3, WAV, FLAC, M4A or OGG. Set the bitrate or sample rate, compare the size before and after, then download. Free, no account, and the file stays on your device.

Drop an audio file here or click to browse

One file, up to 100 MB and 30 minutes. MP3, M4A, AAC, WAV, FLAC, OGG, Opus, WebM audio, AIFF, AMR or WMA.

The file is converted in your browser and is not uploaded.

How to change an audio file's format

Nothing is sent anywhere, so the speed depends on your device, not your connection.

1
Add one file
Drop it or browse to it. MP3, M4A, AAC, WAV, FLAC, OGG, Opus and WebM audio go through your browser's decoder; AIFF, AMR and WMA go through decoders on this page. The length shows if the file's header gives it.
2
Choose the format and its options
Each format shows only what it has: a bitrate for MP3, M4A and OGG, a sample rate for WAV, a compression level and bit depth for FLAC. Mono is there for all five. M4A and OGG are greyed out if your browser has no encoder for them.
3
Compare the sizes and download
You get the expected size where it can be worked out, then the real one next to the original's. Play the result here and save it under the same name with its new ending.

The five output formats and what each is good for

Lossy formats throw detail away to stay small. Lossless formats keep every bit of what they were given.

Format	Kind	One minute	Good for
MP3	Lossy	0.9 MB at 128 kbps	Sharing when you do not know what the other person uses.
M4A (AAC)	Lossy	0.9 MB at 128 kbps	Apple devices and podcast feeds. Apple says AAC sounds better than MP3 at the same bitrate.
OGG (Opus)	Lossy	0.7 MB at 96 kbps	Web use and voice at low bitrates. MDN's suggested minimum for stereo is 96 kbps. Apple devices read it from iOS 18.4 and macOS Sequoia 15.4.
WAV	Uncompressed	10.1 MB at 44.1 kHz stereo	Editors, phone systems and upload forms that ask for it.
FLAC	Lossless	Depends on the audio	A master copy that takes less room. MDN gives up to 40 to 50% off, and the decoded audio is identical.

One MB here is 1,048,576 bytes. AIFF, AMR and WMA can go in but do not come out: this page has no encoder for them.

Lossy, lossless, and why a WAV made from an MP3 is no better

A lossy format makes its file small by removing sound the encoder judges you will miss. That removal happens when the file is first saved and it is permanent. A lossless format such as FLAC only packs the data tighter: MDN describes the decoded result as identical to the original.

So converting an MP3 to WAV or FLAC changes the size and the container, not the sound. Ten minutes at 128 kbps is about 9.2 MB as an MP3 and about 100.9 MB as a 44.1 kHz stereo WAV, and those extra megabytes hold no detail the MP3 did not have. It is still the right move when an editor or a phone system demands a WAV.

Going from one lossy format to another costs a little each time, because the second encoder works on what the first one left. MDN's advice is to avoid lossy compression for audio that will be compressed again. Keep the original, and convert from it rather than from a copy of a copy.

Which format to use

Four jobs that come up often, and what to pick for each.

Sending it by email
MP3 at 128 kbps. Personal Gmail accounts take 25 MB of attachments and turn anything over that into a Drive link, and at this bitrate a minute is about 0.9 MB, so a little over 25 minutes fits. Work and school accounts follow their admin's limit. If it still does not fit, the Audio Compressor picks a bitrate for a target size.
Uploading to a podcast host
Check your host's page first; rules differ. Apple Podcasts Connect takes WAV, FLAC or MP3, refuses single-channel WAV and FLAC, and for RSS feeds takes MP3 or AAC, suggesting 128 to 256 kbps for stereo and strongly recommending AAC. Export from your editing project's original rather than from a compressed copy.
Making an iPhone ringtone
This page does not write M4R, the ringtone file type. The MP3 to M4R Converter does, and helps with the length: Apple says ringtones can be up to 30 seconds long.
Getting it transcribed
Converting adds no words and no clarity, so keep the format you have if the service accepts it. The Audio to Text Converter takes MP3, M4A, WAV, WebM, FLAC and OGG up to 10 minutes and 100 MB, with a free account and 3 transcriptions a month. Convert first only for a type it does not list, such as AIFF, AMR or WMA; a mono MP3 keeps the file small.

When another page does the job better

This converter handles one audio file at a time. A few things belong elsewhere.

Your file is a video
MP4, MOV and MKV files are turned away here. The Video to Audio Converter takes the sound out of them. A WebM is read for its sound on this page, since browsers record audio to that type.
You need a smaller MP3
Converting an MP3 to MP3 is switched off here. The Audio Compressor is built for that, with a size target.
You have a stack of files
The M4A to WAV Converter and the MP3 to FLAC Converter each take up to ten files at once.
You want more on one format
The single-format pages go deeper. MP3 to WAV has a phone-system preset, and there are pages for files coming from WAV, M4A, FLAC and OGG on their way to MP3.

Sources

That was one file, converted once

If your recordings are meetings or calls, the format is rarely the hard part. The ParrotNotes app records on your phone, writes the transcript and adds a summary, free for 100 minutes of recording a month. Ask people before you record them.

Get ParrotNotes free

Audio Format Converter

How to change an audio file's format

Add one file

Choose the format and its options

Compare the sizes and download

The five output formats and what each is good for

Lossy, lossless, and why a WAV made from an MP3 is no better

Which format to use

Sending it by email

Uploading to a podcast host

Making an iPhone ringtone

Getting it transcribed

When another page does the job better

Your file is a video

You need a smaller MP3

You have a stack of files

You want more on one format

That was one file, converted once

Related tools

Audio format FAQ