GrumpToolsAudio
Platforms turn your audio down (or leave it weak) when its loudness misses their target. Pick a preset for YouTube, podcasts, or broadcast, or dial in a custom LUFS target with true-peak control, and get accurate two-pass normalization with a before-and-after readout.
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YouTube / Streaming at -14 LUFS, Podcast at -16 LUFS, Broadcast (EBU R128) at -23 LUFS, plus an adaptive Dynamic mode.
Set any target from -30 to -9 LUFS and a max true peak from -3 to 0 dBTP.
Loudness is measured first, then corrected with linear gain, so results actually land on target instead of drifting.
See measured loudness, true peak, and range for the original and the result, and A/B them with built-in players.
Upload a video and the audio track is normalized while the video stream is passed through untouched.
MP3, WAV, MP4, MOV and other common formats.
Choose a platform preset, the adaptive mode, or a custom LUFS and true-peak value.
Check the before/after readout, A/B the players, and download the result.
-14 LUFS integrated is the practical target. YouTube turns down anything louder; quieter content is left as-is, so mastering near -14 keeps you consistent with other videos.
-16 LUFS is the common recommendation for stereo podcasts (Apple's guideline), with true peaks at or below -1 dBTP. That is exactly what the Podcast preset applies.
Loudness Units relative to Full Scale: the standard way platforms measure perceived loudness over a whole program, rather than just peak levels.
No. The loudness presets apply measured, linear gain with a true-peak ceiling; they are not compression and do not change the character of your mix. The Dynamic mode is the exception: it deliberately evens out level swings over time.
Free accounts can upload files up to 1 GB per file. Pro raises the limit to 3 GB and Premium to 5 GB. File Transfer has its own, much higher limits: 10 GB per transfer on Pro and 100 GB on Premium.
GrumpTools is in beta and runs on a small amount of hardware, so every limit you see is set to what can genuinely finish rather than to what sounds good. We would rather tell you up front than take your file and fail an hour later. These caps are the first thing we raise as the userbase grows and we add capacity, and paid plans are what fund that, so the limits move up over time instead of down.
Files are processed on our servers and deleted automatically within 24 hours. They are never shared, published, or used for anything except running the job you asked for. The one exception is transcription: the Transcript Generator and Auto Subtitles send your audio (never the video, and never your account details) to our speech-to-text provider, Groq, which returns the text. See our Privacy Policy for the full list of processors.
Included with Pro ($9.99/month) and above.