What Is a Limiter in Audio?
A limiter in audio is a dynamics tool that stops any part of a signal from crossing a level you set — the ceiling — so no matter how hard you push the volume, the loudest peaks never go past that line. It sits at the very end of a mastering chain and does two jobs at once: it stops accidental overloads, and it lets you raise a track's overall loudness right up to the edge without distortion. Load a song into the free audio mastering tool, push toward a louder target, and the limiter is what catches the peaks so the whole thing gets louder instead of clipping. If you have read our audio explainers on loudness before, this is the piece that ties them together.
What a limiter actually does
Think of a limiter as a compressor with the ratio turned all the way up. A normal compressor gently reduces the level of anything above a threshold — say, 4 dB over becomes 1 dB over. A limiter is the extreme version of that: anything trying to cross the ceiling gets pulled back so it lands at the ceiling, and nothing gets through above it. That behavior is why the strict kind is called a brickwall limiter — the ceiling acts like a wall the signal cannot pass.
The amount the limiter is clamping at any moment is called gain reduction, usually shown in dB on a meter that dips down when peaks hit. A little gain reduction on the loudest transients is normal and inaudible. A lot of gain reduction, all the time, means you are squashing the life out of the track — the meter is telling you the limiter is doing too much work.
Threshold, ceiling, and gain reduction
Three controls do most of the work, and they are worth defining plainly:
- Threshold (or input gain): how hard you drive signal into the limiter. Push more in and more of it hits the ceiling, so more gets clamped and the average level rises.
- Ceiling (or output ceiling): the absolute maximum output level. Nothing leaves the limiter above this. It is almost always set just below the digital maximum of 0 dBFS — commonly around -1 dBFS — rather than dead-on 0.
- Gain reduction: the read-out, not a knob. It shows how many dB the limiter is shaving off in real time.
Why leave that -1 dBFS of headroom instead of maxing to 0? Because when a track is encoded to a lossy format like MP3 or AAC, the conversion can produce true peak levels slightly higher than the original samples suggested. Reconstructed peaks between samples can overshoot 0 dBFS and clip on someone's phone or laptop even though your file looked clean. A ceiling a touch below 0 leaves room for that overshoot. If clipping is a new idea, our guide to audio clipping and how to avoid it covers the failure mode a limiter is built to prevent.
Why it is the last thing in the mastering chain
A limiter goes at the very end for a simple reason: it needs to see the finished signal. Every stage before it — EQ, compression, stereo adjustments — can add level and create new peaks. Put the limiter last and it catches the combined peaks of everything upstream, so nothing that happens earlier can sneak past the ceiling. It is both a safety net and a loudness maximizer, and it only works as a safety net if it is the final gate.
That ordering is exactly how a real audio mastering chain is built, and it is how the in-browser tool runs too: EQ, then multiband compression, then stereo width, then an output trim, and finally the limiter. The output trim sits before the limiter on purpose — so when you push the master louder, you are driving the limiter like a mastering engineer would, not just slamming the signal into a wall.
Limiter vs compressor
People use "compressor" and "limiter" loosely, but the difference is one of degree, not kind. A compressor is meant to be heard shaping the dynamics — it can be gentle, musical, and slow. A limiter is meant to be not heard; its only goal is to make sure nothing crosses the ceiling, so it uses a very high ratio and a hard (low or zero) knee, reacting fast and aiming precisely at that line. In practice: a compressor evens out a performance; a limiter guarantees a maximum. Most masters use both — compression to control the body of the sound, a limiter to cap the peaks at the end.
How a limiter raises loudness without clipping
Here is the part that makes limiters central to modern music. Loudness is roughly the average level of a track, not the peak level. But the peaks are what stop you from turning everything up — the tallest transient hits the ceiling first and clips. A limiter clamps those tall peaks, which frees you to raise the entire track's average level toward the ceiling without the peaks ever overshooting.
The trade-off is real and worth stating honestly: you are exchanging dynamic range for loudness. Every dB you gain by limiting is a dB of peak-to-average contrast you gave up. A little is invisible. Push too far and you get over-limiting — transients flatten, drums lose their punch, and the limiter starts introducing its own distortion as it works overtime. Our explainer on dynamic range in audio unpacks that contrast, and the loudness war is the story of the whole industry pushing this trade too hard for a decade — the limiter was the weapon.
How to use one in a free browser tool
You do not need a paid plug-in to try this. The in-browser audio mastering tool ends its chain with a brickwall-style peak limiter set near a -1 dBFS ceiling, and it processes everything on your device — your audio never leaves your device. A practical workflow:
- Load the track and pick a loudness target. The tool reports LUFS, the standard loudness measurement, so you can aim for a real number instead of guessing. For where to land, see what LUFS you should master to.
- Push toward the target. As you raise the level, you are driving the output trim into the limiter — the master gets louder and the limiter catches the peaks, exactly like a real chain.
- Watch the gain reduction, not just the loudness. If the peaks are being clamped hard and constantly, back off. Loud is easy; loud and still dynamic is the goal.
- A/B at matched loudness. The tool offers a level-matched comparison so you can hear whether limiting actually improved the track — not just made it louder, which always sounds "better" for a second. This matters because streaming platforms turn loud masters back down anyway; if you are curious how, read how streaming loudness normalization works.
It is free, unlimited, and needs no account or upload.
Frequently asked questions
Is a limiter the same as a compressor? Not quite — a limiter is essentially a compressor with an extreme setting. Both reduce the level of anything above a threshold, but a limiter uses a very high ratio and a hard knee so nothing crosses its ceiling at all, while a compressor uses gentler settings to shape dynamics you are meant to hear. In a full chain you typically use both: compression for body, a limiter for the final peak cap.
Where does a limiter go in the chain? At the very end. A limiter needs to see the finished signal so it can catch the combined peaks of every stage before it — EQ, compression, stereo work. Placed last, it acts as both a safety net against overloads and the tool that maximizes loudness up to the ceiling. In the Vocal Cut mastering tool, the order is EQ, multiband compression, stereo width, output trim, then the limiter.
Can a limiter cause distortion? Yes, if you push it too hard. A limiter clamps peaks cleanly in small doses, but heavy, constant gain reduction flattens transients and introduces audible artifacts — the sound gets harsh and lifeless. This is called over-limiting. Watch the gain-reduction meter: brief dips on loud moments are fine, but if it is pinned down all the time, you are asking for distortion and should back off.
Do I need a limiter to master a song? For a finished, release-ready master, essentially yes. A limiter is what safely raises loudness to a target while guaranteeing no peak clips past the ceiling — without one, you either leave the track too quiet or risk overloads. The good news is you do not need expensive software; a free browser tool with a limiter at the end of its chain does the job for most home masters.