Loudness evener · Free · No upload
Make every song equally loud. Nothing gets uploaded.
Some songs in your playlist are loud and others are quiet, so you keep reaching for the volume knob. fkLevel measures how loud each song really sounds, shows you the differences, and evens them out. Write ReplayGain tags that leave the audio untouched, or make new files at the level you choose, with a safety limit so the sound does not clip. Everything is measured on your device. No account, no watermark.
- LUFS meter
- ReplayGain · MP3 · FLAC
- Album mode
- No upload
What fkLevel can do
Measures loudness, not just peaks
fkLevel reports integrated loudness in LUFS, the way the ear hears it, using the ITU-R BS.1770 method behind the EBU R128 standard. Peak height alone cannot tell you which song sounds louder.
See the whole playlist at once
Every song gets a bar on the same scale, with your target marked. You can see which songs stick out and by how many dB before you change anything.
ReplayGain tags that keep the audio untouched
For MP3 and FLAC files, fkLevel writes ReplayGain tags and copies the sound frames byte for byte. Your tags and cover art stay, and players that read ReplayGain even the songs out.
New files that work in every player
Make new files at the target level for players and car stereos that ignore ReplayGain. MP3 files keep their quality: the level moves inside the file without re-encoding. FLAC, WAV and AIFF files are saved again at the level you want. Titles, artist and cover art are kept.
Safe by default
The true peak is kept under −1 dBTP so boosted songs do not clip. If a quiet song with a high peak cannot reach the target, fkLevel says so and by how much.
Private by design
Your songs are decoded and measured on your device and never uploaded. Files can be saved straight into a folder you choose, in Chrome and Edge.
How to use fkLevel in 5 steps
Choose songs
Press “Choose songs”, then select up to 200 files, or drop them onto the page. Each one is measured as it is added.
Look at the differences
The summary shows the quietest song, the loudest song and the difference in LU. The bars show where each song sits against your target.
Pick a target
Choose −14 LUFS for streaming-style playback, −16 for phones and podcasts, −18 for the ReplayGain reference or −23 for broadcast. Tick “one album” to keep the differences between the songs of an album.
Choose what to make
New files work in every player and keep your tags and cover art. ReplayGain tags leave the sound completely alone but only work in players that read them.
Save
Write the results to a folder, or download them one by one or as a ZIP.
What people use it for
Fix a mixed playlist
Songs from different albums and eras sound equally loud, so the volume stays put.
Prepare a USB stick or phone
Make new files at one level for players and car stereos that ignore ReplayGain.
Check a master
Read the loudness, true peak and loudness range of your own recordings.
The Hi-Fi path
- Your filesFLAC · MP3 · WAV · video
- 1 fkConvert Convert Bit-exact FLAC
- 2 fkLevel Even out LUFS · ReplayGain
- 3 fkAudiophile Listen Spectrum · ABX
- Your earson your own system
Your files stay on your device
fkLevel decodes and measures your songs with your own browser. They are not uploaded to our servers, and we never see them. It only works with files you choose from your device, so please use it for audio you have the right to process.
These pages use anonymous analytics (Google Analytics) for page views and feature use; file names and contents are never part of that data. Read more about privacy.
Browser support
Good to know
- ReplayGain tags only help in players that read them (for example foobar2000, VLC and several Android players). Many car stereos, phones’ default players and some devices ignore them. For those, make new files.
- ReplayGain tags can be written to MP3 and FLAC files. Other kinds of file can be measured and turned into new files, but not tagged.
- New files can be MP3, FLAC, WAV or AIFF. With “Same as source” an MP3 stays MP3, and songs from videos, M4A, Ogg or Opus are saved as FLAC so they are not made lossy twice.
- Without re-encoding, an MP3’s level moves in steps of 1.5 dB, so it can land up to about 0.75 dB from the target. A ReplayGain tag can cover the rest. “Encode again” gives an exact level but costs a little quality each time.
- Titles, artist and cover art are copied into the new files. AIFF files carry no tags.
- Changing the level of a FLAC, WAV or AIFF file changes its samples, so it is no longer identical to the original. Keep your originals. Lowering to 16-bit uses dither.
- A quiet song with a high peak cannot be made louder without clipping, and with the peak limit on it may fall short of the target. The result shows by how much.
- Loudness follows the ITU-R BS.1770 method and was compared with a reference meter on test signals, but the true peak is estimated by oversampling and can differ slightly between meters. Streaming services apply their own normalisation on top.
- Files with a very old tag format (ID3v2.2) or unusual tag features cannot be tagged. Up to 200 files at a time, and a ZIP of results is limited to about 1.5 GB, so use a folder for big batches.
- fkLevel is an early release, and features may be added or changed.
Frequently asked questions
Is fkLevel free? Do I need to sign up?
It is free, with no sign-up, no login and no watermark. Open the page, press “Choose songs” and go.
Are my songs uploaded to a server?
No. They are decoded and measured inside your browser. Your files stay on your device.
Why are some songs louder than others in my playlist?
Songs are mastered at different levels. Newer songs are often mastered much louder than older ones. Loudness evening (normalisation) gives every song the same average loudness so you do not have to touch the volume.
What are the two ways to measure a song?
Peak level is how high the waveform goes. Loudness (LUFS) is how loud the song sounds to the ear over time. Two songs can have the same peak and very different loudness. fkLevel evens out loudness and uses peak only to stop clipping.
What is LUFS?
LUFS means loudness units relative to full scale. It is the unit of the EBU R128 and ITU-R BS.1770 standards, which weight the sound the way the ear hears it and ignore silence. A difference of 1 LU is a 1 dB difference in loudness.
New files or ReplayGain tags: which should I use?
New files work in every player, including car stereos and many phones, so they are the default. ReplayGain tags leave your files exactly as they are and are best if your player reads them, for example when you want to keep lossless originals untouched.
Does fkLevel keep the cover art and tags?
Yes. Titles, artist, album and cover art are copied into the new files. For MP3 files changed without re-encoding, the tag is not touched at all. AIFF files cannot hold tags.
Can it change an MP3 without lowering its quality?
Yes. By default the level is changed inside the MP3 without decoding it, in steps of 1.5 dB, so nothing is lost. If you need the exact level, choose “Encode again”, which re-encodes the MP3 and is slightly lossy.
What does “one album” do?
It gives every song the same gain, worked out from the whole album, so the quiet and loud moments between songs stay as the artist intended. Without it each song is brought to the same loudness.
Which target should I choose?
−16 LUFS suits phones and podcasts, and −14 LUFS matches what many streaming services use. −18 LUFS is the ReplayGain reference and leaves the most room for peaks. If boosting causes clipping warnings, choose a lower target.
Can it work on a YouTube or Facebook link?
No. fkLevel only works with files you choose from your device and never downloads anything from the web.
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