Free, nothing to install
Volume Booster
This volume booster makes an MP3, WAV or video louder by up to 24 dB, or brings it to a loudness target such as −14 LUFS for streaming or −16 for podcasts. A true-peak limiter keeps every peak under −1 dBTP, so it gets louder without clipping. An MP3 comes out at its own bitrate, a WAV at its bit depth, and a video stays a video. It all runs in your browser.
A quiet narration, at podcast level
A narration turned down to −31 LUFS, brought to −16 LUFS with every peak under −1 dBTP.
Loudness −16 LUFS
- no sign-up, nothing to install
- Free
- or −20 dB, in 0.5 dB steps
- +24 dB
- −14, −16, −23 or your own
- LUFS targets
- true-peak limiter
- −1 dBTP
- MP3, WAV, AAC and video
- Format kept
- stays a video, picture untouched
- Video
How do I make an audio file louder?
Open the volume booster and drop in the file. Pick a gain such as +6 dB, or a loudness target such as −16 LUFS for a podcast, and press Play to hear it next to the original. Then press Apply volume: the limiter keeps the peaks under −1 dBTP, and you download it louder, an MP3 as MP3 and a video as video, with its loudness and true peak measured.
Use the volume booster in three steps
The volume booster works on a phone or a computer, in any current browser, with any audio or video file it can read.
Add the file
Drop an MP3, WAV, M4A, FLAC or video in. Its loudness and true peak are read first.
Set the volume
Choose a gain or a loudness target, mark any stretch that needs its own volume, and compare with the original.
Save the louder file
Apply the volume and download it louder, MP3 as MP3, WAV as WAV, with what it measures after.
A volume booster for files, louder without distortion
An online volume booster with exact gains, loudness targets and a true-peak limiter, every result measured.
Any gain, in dB and in percent
From −20 to +24 dB in 0.5 dB steps, each shown as a share of the original amplitude: +6 dB is 200%, +9.5 dB about 300%, +12 dB about 400%. Quick picks for +3, +6, +10 and +12.
Loudness targets in LUFS
Bring a file to −14 LUFS for streaming, −16 for podcasts or −23 for broadcast (EBU R 128), or any level from −30 to −9. The volume booster measures loudness as ITU-R BS.1770 does and meets the target to 0.1 LU, after the limiter, on the file it writes; a file that needs more than +24 dB gets as close as that allows.
A true-peak limiter at −1 dBTP
Peaks between samples can go over full scale even when the samples don’t. The limiter looks 5 ms ahead and measures true peak four times oversampled (BS.1770-5), so no peak of the louder file goes over −1 dBTP, the ceiling streaming services and broadcasters ask for.
Measured before and after
You see the loudness and true peak of the original, what to expect, and then what the new file measures, decoded, with how far the limiter had to pull the loudest peaks down.
The same kind of file out
An MP3 stays an MP3 at its own bitrate and sample rate, with its tags and cover art; a 24-bit WAV stays 24-bit; an M4A stays AAC in browsers that can write it. A FLAC comes back as a 24-bit WAV. Or save it as MP3 or WAV instead.
A louder video that stays a video
Drop in an MP4, MOV or WebM and the picture is copied as it is, untouched; only the sound is made louder and written again. Where a browser can’t write that sound, the volume booster saves it as MP3 and says so.
Sections with their own volume
Drag across the waveform to mark a stretch, such as a quiet speaker or a soft intro, and give it its own gain. Each eases in and out over 50 ms, so there is no jump.
Compare before you save
Play the file through the same limiter the volume booster saves with, and switch between the original and the adjusted sound at the same moment.
Volume booster samples: before and after, measured
Each pair was made by this volume booster’s own code from the site’s voices and music, saved as 192 kbps MP3, and measured on both files. Each opens its settings in the studio.
Volume booster guide: dB, LUFS and true peak
Making a file louder, not a browser tab
Many volume booster extensions turn up whatever a browser tab is playing, for as long as it plays. This volume booster changes the file itself: the louder version plays at that level everywhere, on any device and in any app, and can be shared or uploaded.
To turn up a tab while it plays, use your browser’s own sound settings or an extension; to make a recording, song or video louder for good, use a volume booster for files like this one.
dB and percent
Gain in decibels and gain in percent describe the same thing. Percent is the amplitude as a share of the original: +6 dB doubles it (200%), +9.5 dB about triples it (300%) and +12 dB makes it about four times (400%). A loss is the same the other way: −6 dB is 50%.
How loud a change sounds is another matter: a few dB is a clear step, and about +10 dB is often described as twice as loud.
Why louder files distort, and how a limiter helps
A digital file can’t go past full scale. Turn up a file whose peaks are already near the top and those peaks get cut flat, which sounds harsh. A limiter lowers just the loudest moments, briefly, so the rest can come up.
The peaks that matter are not only the samples: between two samples the sound can rise higher, and a player or an MP3 encoder can push it over full scale. That is the true peak. The volume booster measures it four times oversampled and keeps it under −1 dBTP.
If the limiter has to pull peaks down by more than about 6 dB, loud passages may start to sound squashed. A smaller gain, or a lower loudness target, keeps them natural.
Which loudness target to choose
Loudness in LUFS measures how loud the whole file sounds, not its loudest peak, so two files at the same LUFS sound about as loud as each other.
- 1Streaming (−14 LUFS): music streaming services play at about this level, so music mastered here plays as it was made.
- 2Podcast (−16 LUFS): podcast platforms ask for about −16 LUFS, within 1 dB, with true peaks under −1 dBTP.
- 3Broadcast (−23 LUFS): the EBU R 128 level for European radio and television, with a −1 dBTP ceiling.
Keeping the file’s quality
An MP3 has to be encoded again to change its level. The volume booster writes it at the source’s own bitrate and sample rate, so a 64 kbps voice memo stays small and a 320 kbps song keeps its full quality.
WAV keeps its bit depth: 16-bit with dither, 24-bit or 32-bit float. Encoding can move the level a little too, especially at low bitrates, so the volume booster measures the file it wrote and corrects it until the target holds.
Making a video louder
For a video, only the sound changes. The picture is copied from the original as it is, so it keeps its quality and the job takes about as long as handling the sound.
MP4 and MOV videos keep AAC sound, which Chrome and Edge can write; WebM and MKV keep Opus sound, which Firefox can write too. Where a browser can’t, or the video is too big to rebuild in memory (over 1 GB on a computer, 300 MB on a phone), the volume booster saves the louder sound as MP3.
What people use a volume booster for
Anywhere a file is too quiet, or too loud next to the others, a volume booster sets it right.
Quiet voice memos and lectures
Bring a recording made far from the phone up to a level you can hear on the bus.
Podcast episodes
Every episode to −16 LUFS, the level podcast platforms ask for, with peaks under −1 dBTP.
Songs for a playlist
A quiet demo or an old recording up to −14 LUFS, so it holds its own between other songs.
Videos that are too quiet
Make a phone video’s sound louder and keep it a video, the picture untouched.
One speaker too quiet
Mark that speaker’s lines and give them their own gain, leaving the others as they are.
Broadcast and presentations
Bring a loud clip down to −23 LUFS for broadcast, or a talk to −16 LUFS before it goes on a slide.
Volume booster FAQ
More audio tools
Open the volume booster
Drop a file into the volume booster, set a gain or a loudness target, hear it, and save it louder, measured.