Volume Adjuster

Normalize or change the loudness of an audio file.

Everything runs in your browser. No audio is ever uploaded.

0dB

Adjustment mode

Gain0 dB

This volume adjuster changes how loud an audio file is, in your browser, without uploading it anywhere. It measures what you gave it first, showing peak, estimated true peak, RMS and integrated loudness in LUFS, and then offers four ways to move the level: a flat gain in decibels, peak normalizing, RMS normalizing, or matching a loudness target such as the -14 LUFS that streaming services normalize to. You can A/B the result against the original before you download it.

How to use it

Choose an audio file, or drag one onto the box. The file is decoded in the browser and never leaves your device. Files over 30 MB get a warning, and files over 150 MB are refused because the tab cannot hold them.
Read the Measured levels panel before changing anything. Peak is the loudest single sample, true peak estimates the loudest point between samples, RMS is a rough average level, and the LUFS figure is a loudness measurement weighted to match hearing. Those four numbers usually tell you which mode you actually need.
Pick a mode. Fixed gain moves the whole file by the decibels you set, from -24 to +24 dB, and warns you if that would push the peak past full scale. Peak normalize and RMS normalize both aim at a target level between -30 and 0 dB, the first using the loudest sample and the second using the average.
For loudness mode, press one of the presets for streaming, podcasts or broadcast, or type any target between -36 and -5 LUFS. The true peak is held at -1 dBTP, so if the ceiling stops the file short of the target, the page tells you by how many decibels before you commit.
Press Apply. A progress bar shows how far the render has got, and Apply turns into Cancel while it runs. When it finishes, use the Original and Result buttons to switch the player between the two at the same position, then download the result as a WAV file.

What you can use it for

Rescuing a recording that came out too quiet. An interview recorded at arm's length is often 20 dB below where it should be, and a loudness target fixes that in one pass rather than by guessing at a fader.

Matching a set of clips before an edit. Normalize each one to the same LUFS target and they sit at the same perceived level, which is something peak normalizing cannot do because a peaky clip and a dense one can share the same peak and sound nothing alike.

Preparing a podcast episode. Most podcast guidance lands on -16 LUFS for stereo, and the preset button puts you there without any arithmetic.

Preparing music for streaming. Spotify, YouTube and the rest normalize playback to about -14 LUFS, so pushing a master far louder than that just gets turned back down, usually with less dynamic range to show for it.

Turning a file down. Gain works in both directions, and a negative gain is the fastest way to pull back a clip that is clipping or simply louder than everything around it.

Loudness targets and where they apply

Target	Where it applies	Why that number
-14 LUFS	Spotify, YouTube, Amazon Music	Playback normalization turns louder masters down to roughly this level anyway, so mastering hotter buys volume you do not keep.
-16 LUFS	Apple Podcasts and most podcast guidance	Spoken word mixed slightly quieter keeps room for peaks and stays comfortable on a phone speaker in a noisy place.
-23 LUFS	European broadcast under EBU R128	Broadcast keeps far more headroom so that programs and ads stop jumping in level; the American equivalent, ATSC A/85, uses -24 LKFS.
-1 dBTP	The peak ceiling used here	A decibel of headroom absorbs the overshoot that lossy encoders add when they rebuild the waveform, which is why every platform asks for it.

Accuracy and limits

True peak here is an estimate, and the page says so. Sample peak is simply the largest sample value in the file, while true peak is the highest point the waveform actually reaches between samples, which is what a converter or a lossy encoder has to reproduce. This tool estimates it by oversampling four times with a cubic interpolation between neighboring samples, which catches most of the overshoot a plain peak reading misses, though a certified meter oversamples further and can read a couple of tenths of a decibel higher.

Loudness matching applies one flat gain to the whole file. It is not compression and not leveling. If a recording is loud in one place and inaudible in another, moving all of it together will not fix that, because the LUFS figure is an average across the whole file. The -1 dBTP ceiling can also stop a very peaky file short of the target, and the shortfall note tells you when that happened.

The output is always an uncompressed WAV, so a compressed input comes back much larger. Decoding, measuring and re-rendering all happen in the tab's memory, which is why large files are warned about and very large ones are refused. If you need an MP3 back, run the WAV through a converter afterwards.

Frequently asked questions

What is LUFS, and how is it different from dB?

LUFS measures loudness the way people perceive it, using the frequency weighting and gating defined in ITU-R BS.1770, and it is what streaming services use to decide how much to turn a track up or down. A plain dB reading measures signal level with no regard for how loud it sounds. Two files can share a peak of -0.1 dB and differ by 10 LUFS.

What loudness should I use for Spotify or YouTube?

About -14 LUFS with a true peak no higher than -1 dBTP, which is exactly what the streaming preset does. Going louder does not make you louder on the platform, because playback normalization pulls it back down.

What is the difference between peak, true peak and RMS?

Peak is the largest single sample. True peak estimates the highest point the analogue waveform reaches between samples, which can sit above the sample peak. RMS is an average level over time and correlates loosely with loudness, though LUFS does that job properly by weighting the frequencies the way hearing does.

Why did it not reach my loudness target?

Because raising the file that far would have pushed the true peak past the -1 dBTP ceiling, so the gain stops there and the page reports the shortfall. That happens with peaky material such as solo drums or a sparse acoustic recording. Reaching the target from there needs compression or limiting, which this tool deliberately does not do.

Does normalizing damage the audio?

Applying gain is arithmetic, and it happens in floating point here, so the change itself is clean as long as you do not push past full scale. What can cost quality is the round trip: decoding a compressed file and writing a WAV is fine, but re-encoding that WAV back to MP3 adds another lossy generation.

Is my file uploaded anywhere?

No. The file is read, decoded, measured and re-rendered entirely in your browser. There is no server involved in the processing, and closing the tab discards everything.