Free tool — no account needed
Compare two audio files online. Free, private, loudness-matched.
Drop two files in below and switch between them instantly — same position in the track, matched playback levels, nothing uploaded.
How it works
Three steps, none of which involve waiting for an upload bar.
Drop in two files
Drag your before and after onto the tool — a rough mix and a master, two EQ passes, two renders from different plugins. Nothing is uploaded; the files are read straight off your device.
Toggle and listen
Press play and switch versions with a click or the T key. Playback stays in position, so you hear the same moment of the track on both sides of the switch.
Make it look how you want
Change the layout, colors, and version labels while you listen. This is the real SoundToggle player, so what you style here is what you get if you save it.
Unless you choose to save a comparison, no file ever leaves your computer. Decoding, loudness measurement, and playback all happen in the browser tab you already have open.
Why loudness matching matters
In an unmatched comparison, the louder file wins. Not because it's better — because that's how hearing works. Turn one version up a decibel or two and it reads as fuller, closer, more finished, even when the quieter version is the stronger piece of work.
So the tool measures the integrated LUFS of each file you drop in and matches playback levels before you hear a thing. It's on by default, and it shows you the numbers it measured, so you know exactly how much level difference was taken out of the equation. Only playback gain changes — your files are never modified.
That's the difference between an A/B test and a demonstration. Match the loudness and what's left is the actual work.
What the free tool does
Everything below works without an account.
100% in your browser
Your files never leave your device unless you choose to save. There is no upload step, no server copy, and nothing to delete afterwards.
Loudness matched automatically
Integrated LUFS is measured for each file and playback levels are matched by default. The measured values are shown, so you can see what was corrected.
Compare up to three versions
Two files for a straight before/after, or a third when you need to settle an argument between two candidate masters.
No file size caps
There is no upload limit to hit, because there is no upload. Long, high-resolution files are limited only by your own device.
Lossless playback
Your originals play back as they are — no transcoding, no compression pass in between. What you hear is the file you dropped in.
Make it yours
Layouts, colors, and custom version labels. This is the real SoundToggle player rather than a stripped-down demo widget.
Questions about the compare tool
Is it really free?
Yes. The compare tool is free to use with no account, no trial timer, and no credit card. You only need an account if you want to save a comparison or share it with someone else — and that account is free too.
Do my audio files get uploaded?
No. Everything runs locally in your browser — decoding, loudness measurement, and playback all happen on your own device, and your files never leave it. The only time a file is uploaded is if you choose to save the comparison to an account so you can share or embed it.
What audio formats are supported?
Anything your browser can decode, which in practice means WAV, MP3, FLAC, AIFF, OGG, and M4A/AAC. You can mix formats in the same comparison — a WAV against an MP3 works fine.
Is there a file size limit?
There's no hard cap. Because the files stay on your device, the practical limit is your device's memory — a long, high-resolution WAV will use more of it than a short MP3. Large files take a moment to decode before playback starts.
How does loudness matching work?
The tool measures the integrated LUFS of each file you drop in, then applies playback gain so every version plays back at the same perceived loudness. It shows you the numbers it measured, and it only changes playback level — your original files are never modified or re-encoded.
Can I save or share a comparison?
Yes, with a free account. Saving turns your comparison — the files and the styling you chose — into a shareable SoundToggle player with its own link and an embed code for your own site. Creating the account starts a Studio trial, which supports lossless uploads.
Can I compare three versions instead of two?
Yes. Drop in a third file and the tool compares up to three versions, with loudness matching applied across all of them.
Keep the comparison
Send it to the client instead of describing it.
The comparison you just built — files, labels, and styling included — becomes a shareable, embeddable player the moment you save it to a free account. Signing up starts a Studio trial, so your originals upload lossless.
Start comparing — freeWant the full picture first? See what the SoundToggle A/B player does.