MP3 vs M4A vs WAV vs FLAC: Which Audio Format Should You Download?

When you save audio from YouTube you get a choice: MP3 at two bitrates, M4A, OPUS, WAV, and FLAC. The names sound technical, but the decision comes down to three questions: what will play the file, how much space you can spare, and whether you plan to edit it. This guide compares the formats honestly, including the one fact most converter sites skip, which is that YouTube's audio is already compressed, so a "lossless" download cannot recover anything YouTube never had.

Quick answer

If you just want music that plays everywhere, take MP3 320 kbps. If you live in the Apple ecosystem or want the smallest file, take M4A. If you are going to edit the audio, take WAV. Sizes are approximate and depend on the source.

Lossy vs lossless, in one paragraph

Lossy formats (MP3, AAC in M4A, Opus) shrink audio by discarding parts of the signal that are hard to hear. Done well at a decent bitrate, the loss is inaudible to most listeners on most equipment, but it is permanent, and every additional lossy encode discards a little more. Lossless formats (FLAC) compress without discarding anything, like a ZIP file for audio, and uncompressed formats (WAV) store the raw samples with no compression at all. Lossless and uncompressed files reproduce their input exactly; what they cannot do is improve it.

The catch: YouTube's audio is already lossy

YouTube stores audio as AAC or Opus at roughly 128 to 160 kbps. There is no high-resolution master behind the play button. That has two consequences:

1. A WAV or FLAC download is an exact copy of that lossy stream after decoding. It sounds identical to the M4A or OPUS original, at five to ten times the size. Y-Download offers these formats because they are useful for editing, not because they sound better.
2. An MP3 is a second lossy encode. At 320 kbps the extra loss is negligible; at 128 kbps it is audible on music, which is why 128 kbps is recommended only for speech.

So the real question is not "which format has the best quality" but "which format gives me the source quality in the most convenient package".

MP3

The universal format. Virtually every phone, car stereo, smart speaker, and USB-stick player made this century plays MP3, and tagging support is excellent: Y-Download embeds the title, artist, and square cover art, so tracks look right everywhere. MP3 is the least efficient codec of the group, which is why 320 kbps is needed to preserve the source faithfully. Choose it when compatibility matters more than file size, which for most people is most of the time. The YouTube to MP3 converter page walks through the steps.

M4A (AAC)

M4A is a container holding AAC audio, the codec Apple uses for iTunes and Apple Music and the one YouTube uses for many of its own streams. When you choose M4A, Y-Download saves YouTube's original AAC stream with no re-encoding, so you get exactly the source quality in less than half the size of a 320 kbps MP3. It plays natively on iPhone, iPad, Mac, Android, Windows 10 and 11, and most cars from the last decade. The downsides are minor: some older MP3-only devices skip it, and a few tag editors handle MP4 metadata less gracefully than ID3. For Apple users and anyone short on storage, it is the best choice. See the YouTube to M4A page for details.

OPUS

Opus is the modern open codec YouTube uses for much of its audio, and it is the most efficient of the lossy formats: at the same bitrate it tends to sound better than AAC or MP3. Y-Download saves the original Opus stream untouched. Support is good on Android, in every desktop browser, in VLC, and in most modern desktop players, but iPhones and many car stereos do not play .opus files, and tagging support in music apps is patchy. Pick it if you know your player handles it and you want the smallest faithful copy; otherwise M4A is the safer original-stream option.

WAV

WAV stores uncompressed PCM audio, the same kind of data a CD holds, at about 10 MB per minute. It is the native format of audio editors and digital audio workstations (Audacity, Reaper, Logic, Pro Tools, Premiere, DaVinci Resolve), decodes with zero effort, and can be cut, mixed, and exported repeatedly with no generation loss. Its weaknesses are size and metadata: WAV tagging is inconsistent, so do not expect cover art in your music app, and a two-hour recording is over a gigabyte. Choose WAV when the audio is going into a project, not into a playlist. The YouTube to WAV converter explains the trade-off on the page itself.

FLAC

FLAC compresses audio losslessly to roughly half to two-thirds of the WAV size while supporting rich tags and embedded cover art. From a YouTube source it holds exactly the same audio as the WAV, so its advantages are purely practical: smaller files, proper tags, and a built-in checksum so you can verify the file is intact years later. Support has improved a lot: Android, Windows, VLC, Plex, most network players, and the Files app on iPhone all play FLAC. The notable exception is the Apple Music app on Mac and iPhone, which does not import FLAC; Apple users who want tagged lossless archives should convert to ALAC locally or simply keep the M4A. Choose FLAC for tidy archives of recordings you have the rights to keep.

Recommendations by situation

• Listening on a phone, any brand: MP3 320 kbps, or M4A if storage is tight.
• iPhone, Mac, Apple Music library: M4A. It imports directly and is the original stream.
• Podcasts, lectures, audiobooks: MP3 128 kbps. Speech survives lower bitrates well and the files are small.
• Video editing or music production: WAV. Convert to your project's sample rate inside the editor if it asks.
• DJ software: MP3 320 kbps or WAV; most players accept both, and 320 kbps holds up on club systems as well as the source allows.
• Archiving with tags and cover art: FLAC, or M4A if you use Apple Music.
• Smallest possible file that still sounds like the source: OPUS, with M4A as the compatible fallback.

Whichever you choose, the source is the ceiling. A great-sounding upload will sound great as a 320 kbps MP3 or a small M4A; a poor upload will not be rescued by WAV. For the step-by-step conversion process, see how to convert YouTube to MP3.