How to make a video louder (and what each method actually caps at)

Quiet video, three possible causes. Either the playback chain is turned down somewhere, or the audio inside the file was genuinely recorded at a low level, or nothing is quiet at all and the dialogue is just buried under music. Only the middle one needs a tool. The fix there is gain: open the video volume booster, drop in an MP4, MOV or WebM, and it plays back with the audio boosted live, with a WAV export of the boosted audio when you need to put it back into an edit. It does not re-encode the video file, and there's a real reason for that further down. Check the playback chain first, though. That fix costs nothing and takes half a minute.

The 30-second triage

Do this before you touch any tool. It rules out the free fix.

1. Play a different video from a different source. A YouTube clip, a voice memo, anything. If that is also quiet, the file is fine and your playback is the problem.
2. Check the app's own volume slider, not just the system one. Video players, browsers and social apps each keep a separate level. A player at 20 % inside a laptop at 100 % is still 20 %.
3. Look for a muted browser tab. Chrome, Safari and Firefox all mark a muted tab with a small speaker icon, and the mute survives a page reload.
4. Check where the sound is actually going. Bluetooth earbuds or a speaker that connected quietly in the background is a very common cause of "my video has no sound", and Bluetooth devices hold their own volume separate from the phone's.
5. On a phone, confirm you're adjusting media volume. Press the volume keys while the video is playing. Otherwise you're often moving the ringer volume, which does nothing for playback.

If everything else plays at a sane level and only this one file is quiet, the recording itself is low. Now the tools matter.

Boost the file in your browser, free, nothing to install

This is the fastest route if you want to hear how much louder a file can get before you commit to anything. Load the clip, hit play, and drag the slider while it runs. The file stays on your machine the whole time; there's no upload and no server, so a two-gigabyte camera file doesn't have to go anywhere.

The percentage scale runs from mute to 500 %, where 100 % means untouched. In decibels, since "200 %" isn't a unit anyone learns in school:

Rather than guess, use Smart Boost. It reads every sample and reports the sample peak in dBFS, the RMS level, integrated loudness in LUFS measured to ITU-R BS.1770-4 (K-weighting, 400 ms blocks at 75 % overlap, gated at -70 LUFS absolute and -10 LU relative), and the headroom you have left. Then it names the exact percentage that produces zero clipped samples, keeping 1 dB of margin below full scale, and one click applies it. Say a phone clip peaks at -18 dBFS. That's 18 dB of headroom, so +17 dB is safe with the margin kept, which is about 700 % — past the slider's 500 % ceiling. In other words, you can take that file all the way up without clipping a single sample.

Two things about the measurement, stated precisely. It's sample peak, not true peak (dBTP). Inter-sample peaks after resampling or lossy encoding can sit a fraction of a dB above the sample peak, which is why the tool leaves 1 dB of margin instead of pushing right up to 0 dBFS. And the LUFS figure is there so you can aim at a target yourself. If you want -14 LUFS for YouTube or Spotify, or -16 LUFS for Apple Podcasts, the page tells you how far off you are and you move the slider or click the suggestion. It won't quietly re-master to a target behind your back.

Push past the safe number and a live clip warning tells you what percentage of samples would run past full scale at the current setting. The soft limiter is on by default: a tanh-knee waveshaper that stays transparent below 0.7 of full scale and bends asymptotically toward the ceiling above it. It catches occasional peaks without crunching everything. It's a limiter, not a compressor, so there's no attack or release to tune and no pumping.

Why you get a WAV back, not a louder MP4

Here's the part competing pages skate over. The tool exports the boosted audio as a WAV file (16-bit, 24-bit or 32-bit float), rendered offline faster than real time. It does not write a new video file. Your original MP4 sits untouched on disk. There's no MP3 export either.

That's a deliberate limit. To hand you a louder MP4, a web page would have to either re-record the whole thing in real time (a 20-minute video takes 20 minutes) or ship a full video encoder into your browser, which means a multi-megabyte download and a re-encode that degrades the picture for a change that only affects the sound. Neither is a good trade when the swap takes ten seconds in an editor.

So the workflow is: boost and export the WAV here, drop it onto your video's timeline in whatever editor you already have (CapCut, iMovie, Premiere, DaVinci Resolve, Clipchamp), mute the original audio track, and export once. The WAV is the same length as the source audio, so it lines up at position zero without nudging.

If all you need is to hear the video properly, reviewing a lecture recording, checking what someone said on a doorbell clip, watching a quiet interview, you never need the export. Play it in the tab with the boost on and you're done.

Making a video louder on a phone

Two honest facts first. Nothing on iOS can raise the phone's maximum output volume; the hardware ceiling is fixed and Apple doesn't expose it to apps. And iPhones sold in the EU ship with a headphone level limit switched on, which lives in Settings under Sounds & Haptics, Headphone Safety. Any app promising to break past the hardware limit is lying to you.

What genuinely works on a phone is the same thing as on the web: apply gain to the audio itself. The Increase Volume app for iPhone and the Android version take a file, boost it to 200 %, run it through the same five-band EQ and a bass control, keep your settings saved per track in a library, and export a WAV. It works in airplane mode. It's free, with an optional subscription that lifts the export limit.

The app stops at 200 % and has no limiter or level-matched compare, so for loud, clip-prone files the browser tools are ahead. Use the app when the file already lives on your phone and you don't want to move it. Use the browser when you want the measurement and the safety net.

When dialogue is unclear rather than quiet

Very common, and gain makes it worse. Music and background sit at a comfortable level, speech disappears underneath, and turning everything up 6 dB keeps the same ratio, just louder. You need tone shaping, not volume.

Take the audio into the five-band equalizer and try the Voice preset: -4 dB at 60 Hz, -2 dB at 230 Hz, +3 dB at 910 Hz, +5 dB at 3 kHz, +2 dB at 14 kHz. Cutting the low end pulls out rumble and boominess that mask consonants, and the lift around 3 kHz is where speech intelligibility lives. The Movie preset (+4, -1, +2, +4, +2) is gentler, keeping low-end weight for action scenes while still nudging dialogue forward. Each band is a peaking biquad with Q of 1.0 and a range of ±12 dB, and the response curve updates as you drag.

Use the level-matched A/B button while you compare. It flips between processed and untouched and automatically trims the processed side to the original's peak, so you're judging tone instead of being fooled by "louder sounds better". That's the difference between fixing dialogue and convincing yourself you did. If your problem is the opposite and the video sounds thin on laptop speakers, the bass booster's 120 Hz low shelf, up to +12 dB, is the right control, though small speakers physically can't reproduce much below about 200 Hz no matter what you feed them.

File formats that won't load, and the workaround

Browsers only decode what they ship codecs for. MP4 (H.264 with AAC), MOV and WebM load reliably. MKV and AVI usually don't, and neither do files carrying AC-3 or DTS audio inside an MP4 container, which is why a downloaded film can refuse to open while a phone recording opens instantly.

The workaround is a container change, not a re-encode. Remux the file to MP4 with any tool that offers a copy or stream-copy mode: VLC's convert dialog, or ffmpeg with -c copy. It rewraps the same video and audio data in about the time it takes to copy the file, with zero quality loss. Then load the MP4.

Two more limits. DRM-protected streaming audio is decoded in a protected path the page never sees, so Netflix, Spotify and the rest are off the table. And export is WAV only. Five minutes of 44.1 kHz 16-bit stereo lands around 50 MB, fine for dropping into an editor, large for emailing. Convert to MP3 or AAC at the final export step of whatever editor you use.

The desktop route, when the deliverable is a video file

If someone else will play the result, a client, a course platform, a submission, do the whole job in an editor. The steps are the same everywhere: import the clip, select the audio track, apply gain in dB (editors speak dB, not percent), put a limiter on the master with the ceiling at -1 dBFS, export. Bring the numbers with you. If the volume booster says the file peaks at -21 dBFS and sits at -30 LUFS integrated, you know you have 20 dB before the peak touches -1 dBFS, and that a +16 dB move lands you near -14 LUFS, which is roughly where YouTube normalizes anyway.

Measuring in the browser first takes about fifteen seconds and saves you the guess-render-listen loop that eats real time in an editor.