An audio bitrate converter that tells you the truth
This audio bitrate converter re-encodes MP3, AAC (M4A), Opus and Ogg Vorbis files at the bitrate you choose — 64 kbps for an audiobook, 96 kbps for a podcast, 128 or 192 kbps for music, 320 kbps when a player or upload form insists on it. Each file shows its current bitrate, the new one and the size it will end up, so you know what you gain before you convert.
Use it to fit an album on a small player, get a voice memo under an email or WhatsApp limit, meet a podcast host’s bitrate rule, or turn a WAV or FLAC master into a compact MP3. Title, artist, album and cover art are carried over, and a batch downloads as one ZIP.
Conversion happens on your device with open-source code — Mediabunny (MPL-2.0) to read files, LAME (LGPL) for MP3, the browser’s encoder or FFmpeg’s libavcodec (LGPL) for AAC, WebCodecs for Opus and libvorbis (BSD) through wasm-media-encoders (MIT) — so nothing is uploaded.
How to use the Audio Bitrate Converter
- Drop one or more audio files on the upload area. Each row shows the format, codec, length, sample rate, channels, current bitrate (with CBR or VBR for MP3) and size.
- Leave Output codec on “Same as original” to keep each file’s format, or switch everything to MP3, AAC, Opus or Ogg Vorbis.
- Pick a Target bitrate. The list shows the estimated new size and the change in percent for every file.
- Press Change bitrate and follow the progress; Cancel stops at any time.
- Play the Before and After versions, check the comparison table, then download one file or all of them as a ZIP.
Audio Bitrate Converter features
Real constant-bitrate MP3
LAME 3.100 writes every MP3 frame at exactly the bitrate you choose, from 32 to 320 kbps, which old players, car stereos and upload checkers expect.
Four lossy codecs
MP3, AAC in an M4A file, Opus in Ogg and Ogg Vorbis. AAC uses your browser’s encoder where it can and a WebAssembly build of FFmpeg’s AAC encoder for other bitrates.
Size before you commit
The new size is estimated for each file from its length and the target bitrate, and the real size and percentage are shown after conversion.
Honest warnings
If you ask for more kbps than a compressed file already has, the page says so instead of pretending the result is better.
Tags and cover art kept
ID3, MP4 and Vorbis comment tags are copied, including embedded cover art where the format holds it.
Batch and ZIP
Convert a whole folder at one setting and save the results together.
Bitrate and file size
File size is simply bitrate × duration ÷ 8. A 4-minute song at 128 kbps is 128,000 × 240 ÷ 8 = 3.84 MB, whatever the music sounds like. Halving the bitrate halves the size.
| Bitrate | Size per minute | Good for |
|---|---|---|
| 48–64 kbps | 0.36–0.48 MB | Speech, audiobooks, voice notes (mono is best) |
| 96 kbps | 0.72 MB | Podcasts, Opus music at very good quality |
| 128 kbps | 0.96 MB | Everyday music in AAC, Opus or Vorbis; acceptable MP3 |
| 192 kbps | 1.44 MB | Music in MP3 for most listeners |
| 256–320 kbps | 1.92–2.4 MB | Archival lossy copies, DJ libraries, strict upload rules |
Why raising the bitrate does not raise quality
Lossy encoders throw information away permanently. Re-encoding a 128 kbps MP3 at 320 kbps gives a file two and a half times larger that sounds the same as the 128 kbps original — or very slightly worse, because every decode-and-re-encode adds a little generation loss. That is why the converter warns you when the target is above the source bitrate.
The useful direction is down: shrinking a 320 kbps file to 192 or 128 kbps saves a lot of space with little audible change. For the best result start from the highest-quality source you have, ideally a WAV or FLAC, and encode once.
Which codec to choose
- MP3 plays everywhere, from 20-year-old players to smart speakers. It needs the most bits for the same quality.
- AAC (M4A) is the default for Apple devices and YouTube and sounds better than MP3 at the same bitrate.
- Opus is the most efficient: 96 kbps stereo is very good, and 32–48 kbps is clear for speech. It plays in browsers, Android and most modern apps, but not in every car stereo.
- Ogg Vorbis is a royalty-free alternative used by games and some players. Its bitrate is variable, so the value you pick is a nominal average.
Related tools
Going mono halves the bits a voice recording needs — try the Stereo to Mono Converter first. To change the sample rate rather than the bitrate, use the Audio Sample Rate Converter, and to get audio out of a video use Video to MP3.
Audio Bitrate Converter FAQ
How do I change the bitrate of an MP3?
Drop the MP3 here, leave the codec on “Same as original”, choose a target bitrate such as 128 kbps and press Change bitrate. The audio bitrate converter writes a new constant-bitrate MP3 with the same tags.
Will converting 128 kbps to 320 kbps improve the sound?
No. Detail removed by the first encode cannot be restored, so the file only gets bigger. Keep the original bitrate unless a service requires a minimum.
What bitrate should I use for a podcast?
For speech, 64–96 kbps mono MP3 or 48–64 kbps Opus sounds clean and keeps episodes small. Use 128 kbps stereo if the show has a lot of music.
Why is my converted file not exactly the size shown?
The estimate uses length × bitrate. Containers add a few kilobytes of headers and cover art, and AAC, Opus and Vorbis vary the bitrate a little from moment to moment around the target.
Can I convert WAV or FLAC to a lower bitrate?
Yes. Lossless files have no lossy bitrate to keep, so with “Same as original” they are encoded as MP3 at the bitrate you choose; pick AAC, Opus or Vorbis instead if you prefer.
Is this bitrate converter free and private?
Yes. There is no sign-up, watermark or file limit, and the audio never leaves your device.