How to Master a Song Online for Free
Updated October 2026 · by Loopin
You don't need a studio or paid software to get a clean, loud, release-ready master. With Loopin Mastering you can master a song online for free, right in your browser — and because everything runs on your device, your file is never uploaded. Here's the whole process, plus the checks that decide whether the result is ready to release.
Before you start: is the mix ready?
Mastering makes a finished mix sound finished everywhere. It cannot rebalance a vocal that is buried or fix a kick that fights the bass. Before you bounce, play the mix quietly on a phone speaker and once on headphones. If something only works on one of them, fix it in the mix first. Our mixing vs mastering guide covers where one job ends and the other begins.
1. Bounce a stereo mixdown
Export your finished mix as a single stereo WAV (best quality) or MP3. Use the session's sample rate and 24-bit if your DAW offers it. Leave a little headroom: peaks around −3 to −6 dBFS give mastering room to work. Take any limiter or loudness maximiser off the master bus, because mastering will handle loudness and a limiter on the mix hides problems that then come back louder.
Trim long silence at the start and end, but leave the natural tail of the last note. If you only have an MP3 from a collaborator, it will still work; ask for the WAV if you can get it, because an MP3 has already lost some detail.
2. Add it to the tool
Open Loopin Mastering and drag your file onto the drop zone (or browse for it). You'll see where your track starts, including its loudness and true peak, before you choose anything. If you want a fuller readout of your mix first, including loudness range and what each platform would do to it, run it through the free LUFS and true-peak meter.
3. Pick a feel
Choose the style that fits your genre: Warm, Punchy, Crisp, Wide, Vintage, Club, Lo-fi or Cinematic. Loopin listens to your whole mix first, then sets tone, punch, width and loudness to suit it and the feel you chose. A quick guide:
- Punchy (about −11 LUFS) and Club (about −10) for hip hop, trap and club music that needs to hit hard.
- Crisp and Wide (about −14) for vocal-led pop and melodic electronic music.
- Warm (about −15) for thin or bright recordings, acoustic songs and R&B.
- Cinematic (about −16) for dynamic, wide material and spoken word.
- Vintage and Lo-fi when you want character and a softer top end.
Try two or three. The right feel is usually obvious within ten seconds of the chorus.
4. Compare Original vs Mastered
Use the A/B toggle to flip between your original and the master. It's loudness-matched, so you judge the tone and not just "louder sounds better". Listen for three things: does the vocal stay in front, does the low end stay controlled, and does the loudest section still feel bigger than the verse? Toggle mono to check the track still holds up on phone and club speakers.
If the master sounds harsh or muddy in the same place on every feel, that is the mix telling you something. Go back, fix it at the source (often 1 to 2 dB on one channel), bounce again and re-master.
5. Download your master
Hit download and you get a mastered file at the loudness of the feel you picked, with true peak kept under the ceiling streaming services ask for (about −1 dBTP, or −2 dBTP on louder masters, which is what Spotify advises for masters louder than −14 LUFS). Free, no account, nothing uploaded.
6. Check it before you release
- Play the master on at least two systems you know well: earbuds and a car or laptop are enough.
- Measure it. Integrated loudness and true peak should match what you expect for the feel; the LUFS meter shows both.
- Compare it with a commercial song in your genre at matched loudness. Spotify and YouTube play music at about −14 LUFS and Apple Music at about −16, so a louder master will simply be turned down.
- Name the file clearly (artist, title, “master”, date) and keep the unmastered mix alongside it, so you can re-master later without starting again.
For platform-by-platform targets, see mastering for Spotify, Apple Music and YouTube. For what the numbers mean, see what is LUFS.
Tips for a better master
- Fix problems in the mix first — mastering enhances, it can't rescue a clipped or muddy mix.
- Reference a commercial song in your genre and match by ear, level-matched.
- Don't chase maximum loudness. Around −14 LUFS sits close to where several big services play music, and it keeps your dynamics.
- Master every song on an EP with the same feel unless one clearly needs something else; it keeps the release consistent.
Producing beats every week or mastering for clients? See mastering for producers and mastering for engineers.
Try it now: open the free Loopin Mastering tool — drop in an MP3 or WAV, pick a feel, and download a streaming-ready master. Nothing leaves your device.
Frequently asked questions
Can I master a song online for free?
Yes. Loopin Mastering lets you add a mix, pick a feel, compare it with the original at matched loudness and download the master.
Should I upload a WAV or an MP3?
A WAV if you have one. Mastering brings out detail, and an MP3 has already discarded some. An MP3 still works and will still sound better mastered.
How loud should my mix be before mastering?
Leave peaks around −3 to −6 dBFS and keep any limiter off the master bus. The integrated loudness of the mix matters less than having headroom.
Which feel should I pick?
Start from your genre: Punchy or Club for hard-hitting beats, Crisp or Wide for vocal pop, Warm for acoustic or thin recordings, Cinematic for dynamic material and speech. Then trust the A/B.
Can I master stems or a single vocal?
No. Use a stereo mixdown of the finished song. Mastering a lone vocal or separate stems will not give you a balanced result.