Free Online Mastering Tool
Master your track right in your browser — loud, balanced, and streaming-ready. No signup, no upload, no watermark: every step runs on your device and your audio stays private.
In short: Selekt Free Online Mastering Tool is a 100% in-browser tool that masters a finished mix to about −14 LUFS / −1 dBTP using the Web Audio API — no upload, no account, no watermark — and exports a full-quality WAV.
Last updated: July 2026
Drop your mix here or click to browse
WAV · MP3 · FLAC · OGG · M4A
Then dial it in: choose a style — General, Hip-hop, Pop, EDM, Acoustic, Classical, Rock, Lo-fi — and a loudness target for Spotify, Apple Music, SoundCloud, or club.
Selekt’s free online mastering tool lets you master a track online, instantly, for free — drop in a finished mix and get a loud, balanced, streaming-ready master back in seconds, right in your browser. Add a WAV, MP3, or FLAC, pick a style, and download the mastered WAV. There is no account, no watermark, and no upload: every step runs on your own device, so your unreleased music stays private. Already tried LANDR? See how the two compare before you master.
What is online mastering?
Mastering is the final stage of music production — the polish applied to a finished mix so it sounds loud enough, tonally even, and consistent with commercial releases across phones, earbuds, car speakers, and club systems. It is different from mixing: mixing balances the individual tracks — drums, bass, vocals — into one finished stereo file, usually in a DAW; mastering takes that finished stereo mix and polishes it. This tool handles the mastering step. Online mastering does that in software instead of a dedicated studio. Traditional online services upload your track to a server and process it in the cloud; this tool runs the same kind of mastering chain — EQ, compression, limiting, and loudness normalization — locally in your browser, so it is free, instant, and private.
How to master a song for free online
- Drop in your finished mix — WAV, MP3, FLAC, OGG, or M4A. It loads from your disk; nothing uploads.
- Pick a style — General/Streaming works for most material, or choose Hip-hop, Pop, EDM, Acoustic, Rock, or Lo-fi.
- Master it — the tool analyzes your track and applies a matching EQ, glue compression, and a true-peak limiter to a streaming loudness target.
- A/B and export — toggle original vs. mastered, check the before/after loudness, and download your mastered WAV.
Want the full walkthrough? Our guide on how to master a song for free online covers LUFS targets for Spotify and Apple Music and how in-browser mastering works.
What loudness should a master be? LUFS targets for Spotify, Apple Music & YouTube
Streaming platforms normalize playback loudness, so chasing the loudest possible master no longer wins — it just gets turned down (and often distorted). The widely used target is about −14 LUFS integrated with a −1 dBTP true-peak ceiling, which is where Spotify, YouTube, and Amazon Music sit; Apple Music normalizes a little quieter, around −16 LUFS. This tool masters to roughly −14 LUFS / −1 dBTP by default and shows you the exact before-and-after loudness, so your track lands in the right range for streaming without clipping. Want the exact number for each platform? See our guide to LUFS targets for Spotify, Apple Music & YouTube.
Free online mastering vs. paid services like LANDR
Paid cloud services — LANDR, eMastered, CloudBounce — upload your track and run reference-matched, ML-tuned mastering on their servers, usually behind a subscription or a per-track fee, often gating the high-quality download. This tool trades that ML tuning for being genuinely free and private:
| Feature | Selekt | LANDR | BandLab | eMastered |
|---|---|---|---|---|
| Price | Free | Subscription | Free tier + paid | Subscription / per‑track |
| Account required | No | Yes | Yes | Yes |
| Uploads your audio | No — stays on your device | Yes (cloud) | Yes (cloud) | Yes (cloud) |
| Free full-quality WAV | Yes | Typically gated | Limited | Typically gated |
| Processing location | Your browser (local) | Cloud | Cloud | Cloud |
| Best for | Free, private, fast first pass | Reference-matched ML for a release | Quick cloud master | ML master with tweaks |
The honest caveat: for a critical commercial release, a paid reference-matched service or a human mastering engineer can still go further than any free tool. This one is a fast, free, private first pass — and it never touches a server. (Competitor pricing and features change; check their sites before deciding.)
Weighing Selekt against LANDR specifically? Read the full Selekt vs LANDR comparison — including LANDR’s free-tier WAV limit and when their paid bundle is actually the better call.
Private by design: master unreleased music without uploading
Producers and composers are rightly cautious about sending unreleased work to a stranger’s server. Because this tool processes everything in your browser with the Web Audio API, there is no upload and no file sitting in a cloud account — the audio stays on your hard drive from start to finish. It is the same local-first principle the rest of Selekt’s tools follow: your work is yours.
Concretely: your audio is decoded and processed in-memory through the browser’s Web Audio API, and zero bytes of your file are ever sent to a server — there is no upload step to opt out of and no copy to delete later.
When to use a free in-browser master
Whether you master a track online for free once or run through a dozen beats, here’s when this fits best:
- Demos and drafts — get a release-level loudness on a rough mix before you share it.
- Beat tapes and loops — bring a folder of beats to a consistent, streaming-ready level.
- Content and video — master a track for YouTube, reels, or a podcast without a queue or a fee.
- A fast first pass — hear your mix “finished” instantly, then decide whether a critical release needs a human engineer.
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Frequently asked questions
Is this online mastering tool really free?
Yes — completely free, with no account, no watermark, and no upload. It is instant mastering: the tool runs entirely in your browser on your own device, so there is no queue, no per-track cost, and nothing to pay for. You can master as many tracks online as you like and download each one as a WAV.
Does this tool mix and master my song, or just master it?
Just mastering. Mixing — balancing individual tracks like drums, bass, and vocals into one finished stereo file — happens first, in a DAW. This tool takes that already-mixed, finished stereo file and masters it: matching EQ, glue compression, a true-peak limiter, and loudness normalization to a streaming-ready level. If your mix is done, drop it in here for a free, instant master; it will not combine separate tracks for you.
Do I have to upload my track or create an account?
No to both. There is no sign up and no upload: your file is read straight from your disk into the browser and processed locally on your device. That makes it a genuinely free online mastering tool with no account and no waiting in a queue — just drop a mix in and master it.
Is it safe to master unreleased music here?
Yes. Because nothing is uploaded, your unreleased music never leaves your computer and never touches our servers — there is no file sitting in a cloud account to leak. If you have ever wondered whether it is safe to upload unreleased tracks to an online mastering site, this tool sidesteps the question entirely: the audio stays on your device.
How does in-browser mastering work?
When you drop in a mix, the tool measures its loudness, true-peak level, and tonal balance, then applies a matching EQ, gentle glue compression, a true-peak limiter, and loudness normalization toward a streaming target (about −14 LUFS, −1 dBTP). All of that is standard mastering DSP and runs on your CPU via the Web Audio API — no AI server, no GPU, no queue.
How loud will my master be (LUFS for Spotify, Apple Music, YouTube)?
The tool targets roughly −14 LUFS integrated loudness with a −1 dBTP true-peak ceiling — the balance Spotify, YouTube, and Amazon Music normalize around (Apple Music sits a little quieter near −16 LUFS). Some styles, like EDM and hip-hop, push a touch louder. You always see the before and after loudness, so you know exactly what changed.
Is there a watermark, and do I get a WAV?
No watermark, and yes — you download a full-quality mastered WAV. Many free mastering tools either stamp a watermark on the preview or only let you export a low-quality MP3 until you pay. This one exports a clean 16-bit WAV for free.
Free online mastering vs. LANDR or BandLab — what is the difference?
LANDR, BandLab, and eMastered are cloud services: you upload your track, their servers process it, and a free tier often gates the high-quality download or adds a subscription. This tool runs the mastering chain in your browser instead, so it is free, needs no account, never uploads your audio, and exports a WAV — at the cost of the reference-matched ML tuning a paid service can offer on a critical release. It is an honest, fast, free first pass.
Will it sound as good as a professional mastering engineer?
It gives you a loud, balanced, streaming-ready master for free, in seconds — perfect for demos, drafts, loops, beat tapes, content, and fast turnarounds. A human mastering engineer or a paid service can still go further on a critical commercial release. This is an honest first pass, not a replacement for a pro on your most important record.
What files can I master, and what headroom should I leave?
Drop in a finished stereo mix as WAV, MP3, FLAC, OGG, or M4A. You get back a mastered 16-bit WAV you can download and release. For the cleanest result, leave a little headroom in your mix (peaks around −6 dB) before mastering rather than a mix already slammed to the ceiling.
Your next step after mastering
Selekt is a workspace for producers and composers — cleared samples, studio tools, and a verifiable receipt for everything you make. Master your track, screen it, then build the next one from a library you can actually clear.
