Master unlimited tracks,
all free and instant.

Drop in a track, pick a sound, hear the difference and download — free.

Drop a track to master

MP3 or WAV · or

Your audio never leaves your device.

Eight ways to make it sound finished

Every style is a full mastering chain — EQ, compression, stereo and a true-peak limiter — tuned to a feel. Drop in a track to hear them on your own song.

WarmRound low-mids, analog glow.
PunchyTight, hard-hitting lows.
CrispAir up top, tamed esses.
WideBig stereo, bass kept mono.
VintageTape colour and roll-off.
ClubLoud, smiley, club-ready.
Lo-fiSoft, narrow and hazy.
CinematicDeep, wide, dynamics kept.

What is mastering?

Mastering is the final step before you release a song. It's the polish that makes a mix sound finished and consistent everywhere it's played — earbuds, a laptop, a car, a club PA. A good master does three things: it balances the tone so nothing is too boomy or harsh, it controls the dynamics so the quiet and loud sections sit together, and it raises the loudness so your track holds its own next to commercial releases on Spotify, Apple Music and YouTube.

Mixing vs mastering

Mixing balances the individual tracks inside a song — vocals, drums, bass, synths. Mastering works on the finished stereo file as a whole: tone, dynamics, loudness and stereo width. You mix so the parts sit together; you master so the song translates everywhere and sounds as loud and clean as a professional record. Read more on mixing vs mastering →

Loudness and true peak (LUFS, dBTP)

Loudness is measured in LUFS (Loudness Units relative to Full Scale). Streaming platforms normalise everything to around −14 LUFS, so pushing a master far louder than that just costs you dynamics — the platform turns it back down anyway. The other number that matters is true peak (dBTP): leaving a −1 dBTP ceiling prevents the inter-sample clipping that MP3/AAC codecs and phone DACs can introduce. Loopin Mastering measures and targets both automatically. Learn what LUFS means →

Master your song free, in your browser

Loopin Mastering runs entirely on your device. Upload a stereo mixdown as an MP3 or WAV, pick a feel that fits your genre, and hear the mastered version against the original instantly — loudness-matched, so you judge the tone honestly rather than just "louder sounds better". When it's right, download a mastered WAV at about −14 LUFS with a −1 dBTP ceiling. No account, no waiting, and nothing leaves your device. Follow the step-by-step guide →, or see how to master for Spotify, Apple Music and YouTube →.

Mastered it?
Now write the next one.

Loopin keeps your beats, lyrics and takes in one place — so the song actually gets finished.

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Mastering, answered

How do I master a song online?

Drop your MP3 or WAV into Loopin Mastering, choose a preset, listen to Original versus Mastered, then download the mastered file. It's free and runs entirely in your browser.

Is it really free?

Yes — free to master your track, with no account or sign-up.

What files can I master?

MP3 and WAV (plus most formats your browser can decode). Use a stereo mixdown of your finished song.

Does my audio get uploaded anywhere?

No. Everything is processed locally in your browser — your file never leaves your device.

What's the difference between mixing and mastering?

Mixing balances the individual tracks of a song (vocals, drums, bass). Mastering is the final polish on the finished stereo mix — tone, dynamics and loudness — so it sounds consistent everywhere.

How is this different from LANDR, BandLab or eMastered?

Loopin Mastering is free and runs entirely in your browser, with nothing uploaded to a server. Paid tools like LANDR, eMastered or CloudBounce process on their servers and charge per track or by subscription. Loopin gives you genre feels, an instant loudness-matched A/B and a true-peak-limited WAV at no cost — a genuine free alternative for most songs.

How much does mastering cost?

A human mastering engineer typically charges around $30–100+ per song, and AI mastering subscriptions run monthly. Loopin Mastering is free — no per-track fee, no subscription and no account.

Is online mastering any good?

For demos, singles and most independent releases, yes — a good online master gets your loudness, tone and peaks right so the track translates everywhere. For a major commercial release you may still want a human engineer, but Loopin gets you a clean, streaming-ready master in seconds for free.

Writing the song too? Loopin keeps your beats, lyrics and takes in one place →