A podcast converter that makes your episode ready to publish
Recording the episode is the fun part; getting the file right for Apple Podcasts, Spotify and every other app is not. This podcast converter takes the WAV, MP3, M4A or video you exported from your editor and produces a publish-ready MP3 in one go: mono or stereo at a podcast-typical constant bitrate, loudness normalised to −16 LUFS, peaks held under −1 dBTP, dead air trimmed from the start and end, and the episode details written into ID3 tags — title, show, host, episode number, description, cover art and even chapters.
Loudness is measured the way the platforms measure it, with the ITU-R BS.1770 algorithm, and the finished MP3 is decoded and measured again so the numbers you see are those of the actual file. Everything runs in your browser, so a two-hour unreleased episode never leaves your computer.
How to use the Podcast Converter
- Drop the episode file on the upload area. The converter measures its loudness, true peak and the silence at each end.
- Choose a Loudness target (−16 LUFS suits most shows), the True-peak ceiling, mono or stereo and the MP3 bitrate.
- Leave Trim silence at the start and end on, or adjust its threshold and how much room to keep.
- Fill in the episode title, show name, host, episode number, year and description, add a square cover image and, if you like, a chapter list.
- Press Convert to podcast MP3. The MP3 downloads when it is ready, with a summary of its measured loudness, peak, size and tags.
Podcast Converter features
BS.1770 loudness normalisation
K-weighted, gated integrated loudness — the measurement behind LUFS — with a gain correction pass if limiting changes the result.
True-peak limiter
A look-ahead limiter checks peaks between samples with 4x oversampling, so the MP3 stays under your ceiling without audible pumping.
Podcast-typical MP3
Constant-bitrate MP3 from the LAME encoder (LGPL), run through Mediabunny (MPL-2.0), at 64–256 kbit/s, mono or stereo, 44.1 or 48 kHz, with the file size per hour shown before you convert.
Complete ID3 tags
Title, show (album), host (artist), episode number, year, genre “Podcast”, a description comment and front-cover art in an ID3v2.3 tag.
Chapters in the MP3
Chapter lines become ID3 CHAP and CTOC frames, which Apple Podcasts and many other players show as chapters.
Silence trimming
Removes dead air before the intro and after the outro, keeping a little room and adding 10 ms fades so nothing clicks.
What the platforms ask for
Apple’s audio requirements for podcasters recommend MP3 at 44.1 or 48 kHz, 64–128 kbit/s for mono and 128–256 kbit/s for stereo in RSS feeds, an overall loudness of about −16 LKFS with a ±1 dB tolerance, and true peaks no higher than −1 dBFS, measured with ITU-R BS.1770. The AES TD1004 recommendation for streaming also suggests −16 to −20 LUFS with a −1 dBTP maximum. Other platforms normalise playback themselves, so a file prepared to Apple’s guidance plays at a sensible level almost everywhere.
| Setting | Speech show | Music-heavy show |
|---|---|---|
| Channels | Mono | Stereo |
| MP3 bitrate | 96 kbit/s (64–128) | 128–192 kbit/s |
| Size per hour | 43.2 MB at 96 kbit/s | 57.6 MB at 128 kbit/s |
| Loudness / true peak | −16 LUFS / −1 dBTP | −16 LUFS / −1 dBTP |
−16 or −19 LUFS for a mono show?
BS.1770 measures a mono file as one channel. Most phones and speakers play a mono podcast on both sides at once, which sounds about 3 dB louder than the measurement suggests, so some producers target −19 LUFS for mono to match −16 LUFS stereo. Others keep −16 LUFS because many apps don’t apply that offset. Both are reasonable — what matters is that every episode is normalised the same way.
Cover art, tags and chapters
Apple asks for show artwork as a square JPG or PNG of 1400 × 1400 to 3000 × 3000 pixels without transparency. The image embedded in each MP3 is shown by players and car stereos; 1400 px keeps the file small. Your RSS host’s episode title and description usually take priority in podcast apps, so keep them consistent with the tags. Chapter times refer to your original file and are shifted automatically when silence is trimmed. Some hosting companies rewrite MP3 files and drop ID3 chapters, so check yours after uploading.
Podcast Converter FAQ
What is the best MP3 format for a podcast?
For a speech show, mono MP3 at 96 kbit/s and 44.1 kHz — about 43 MB an hour. Use stereo at 128–192 kbit/s if music or sound design matters. This podcast converter shows the file size per hour for every bitrate.
How do I normalise a podcast to −16 LUFS?
Drop the episode here, keep the −16 LUFS target and the −1 dBTP ceiling, and convert. The tool measures the loudness with BS.1770, applies the gain, limits peaks and then measures the finished MP3 to confirm it.
Will normalising make my podcast sound compressed?
No compression is applied, only overall gain and a peak limiter that touches the loudest instants. If your recording is very dynamic, light compression in your editor first makes speech more even.
Can I add chapters to an MP3?
Yes. Type one chapter per line, such as “12:30 Interview”. They are written as standard ID3 chapter frames that Apple Podcasts and many other apps read.
Is my episode uploaded?
No. Decoding, measuring, limiting and MP3 encoding all happen in your browser, so unreleased episodes stay private.
Which files can I convert?
WAV, MP3, M4A/AAC, FLAC, Ogg Vorbis, Opus and the audio of MP4, MOV, WebM or MKV videos — anything your browser can decode.