LUFS checker for video and audio files
Drop a video or audio file and read its integrated loudness in LUFS, measured in your browser the way ITU-R BS.1770 describes. See how far it is from -14 LUFS and from the levels Spotify, Apple Podcasts and EBU R 128 publish. Free, with no sign-up, and the file opens on this device and is never uploaded.
Your reading appears here: the integrated loudness in LUFS, the length measured, and how far it is from -14 LUFS.
Integrated loudness
-14.0LUFS
- File
- Measured
- Channels
- Against -14 LUFS
The ticks are the published levels in the table below: -23 EBU R 128, -19 Spotify Quiet, -16 Apple Podcasts, -14 Spotify Normal, -11 Spotify Loud. The scale runs from -30 to -6 LUFS.
Level and caption it in Burncaps
Burncaps burns animated word-by-word captions into a talking video, in your browser, and finds the best moments of a long recording as ranked, captioned 9:16 clips whose sound is levelled to -14 LUFS. The captioned whole video keeps its sound as recorded.
Free: 2 videos every 30 days, each with captions and up to 3 clips, no watermark, no sign-up. Then try Captions + Clips free for 7 days, no card. Captions + Clips is $29 a month for unlimited clips and captions; Captions is $9.98 a month or $49 once.
Check a file's loudness in three moves
Drop the file
A video (MP4, MOV, WebM) or an audio file (MP3, WAV, M4A, FLAC, OGG), up to ten minutes. It opens in this page from your device and is never sent anywhere, which you can check in your browser's network tab on a computer.
Read the number
The big number is the file's integrated loudness: its level averaged over the whole file, with silence and the quietest parts left out, as BS.1770 defines it. The line under it says how far that is from -14 LUFS, in loudness units (LU), where 1 LU is 1 dB.
Compare or fix
The table below sets your reading against the levels Spotify, Apple Podcasts and the EBU publish. To move the file, change its gain by the difference and measure it again.
What LUFS is
LUFS stands for loudness units relative to full scale. It measures how loud a recording sounds to a listener, which is not the same as how high its loudest peak goes: a file with one sharp bang can peak at the maximum and still sound quiet, and a steady, compressed file can sound much louder at the same peak. One LU is one decibel, so a file at -16 LUFS is 2 LU quieter than one at -14.
How the number is made
The method is ITU-R BS.1770. The sound is first filtered the way an ear hears it, with a lift for the high notes and a cut for the lowest rumble (the K-weighting). Its power is then measured in blocks of 400 milliseconds that overlap by 75%. Blocks quieter than -70 LUFS are dropped, and so are blocks more than 10 LU below the average of what is left, so the pauses between sentences do not pull the number down. What remains is averaged into the integrated loudness. The ITU calls the unit LKFS and the EBU's R 128 calls it LUFS: it is the same scale. The meter on this page is the one Burncaps levels its clip sound with.
Loudness levels that sources publish, read 3 November 2026
These are the figures each source prints in its own pages. They are not rules every app follows, and none is a promise about how your file will sound there. After you drop a file, the third column shows how far it is from each level.
| Source | Published level | Your file | What the source says |
|---|---|---|---|
| Spotify, Normal (the default) | -14 LUFS | Drop a file | Spotify says: "We adjust tracks to -14 dB LUFS, according to the ITU 1770 standard." It applies this while a track plays. Its web player and third-party devices such as TVs and speakers do not normalise. Spotify for Artists, Loudness normalization on Spotify. |
| Spotify, Loud (Premium setting) | -11 LUFS | Drop a file | A setting Premium listeners can choose in the Spotify app. Spotify for Artists, Loudness normalization on Spotify. |
| Spotify, Quiet (Premium setting) | -19 LUFS | Drop a file | A setting Premium listeners can choose in the Spotify app. Spotify for Artists, Loudness normalization on Spotify. |
| Apple Podcasts | around -16 LKFS, plus or minus 1 dB | Drop a file | Apple recommends an overall loudness "around -16 dB LKFS, with a +/- 1 dB tolerance" for the audio you deliver. The third column says whether your file is inside that range. Apple Podcasts for Creators, Audio requirements. |
| EBU R 128 (broadcast) | -23 LUFS | Drop a file | The EBU recommends "an average programme loudness of -23 LUFS" for broadcast programmes. Version 5.0, November 2023. EBU, R 128 (version 5.0, November 2023). |
| YouTube | No level published | Not compared | YouTube Help describes Stable volume, a viewer setting that evens out quiet and loud parts, and gives no LUFS number. YouTube Help, Control video volume on your device. |
Why Burncaps uses -14 LUFS, and what YouTube says
-14 LUFS is Burncaps's own level for clips. It is the level Spotify publishes for its default setting, and many guides by other people report it for video apps. It is our choice for clips, not a rule that YouTube prints.
YouTube publishes no level. Its Help page Control video volume on your device (read 3 November 2026) says stable volume is on by default for viewers, evens out the range between quiet and loud, is not available for every video, and is turned off for YouTube Music and official music videos. It gives no number in LUFS, so this page gives none as YouTube's. We recheck every figure on this page monthly and change the date when we do.
How to bring a video to -14 LUFS
Loudness is changed with gain, a volume change in decibels. The gain you need is the level you want minus your reading: a file at -19.3 LUFS needs +5.3 dB to reach -14, and one at -9.8 LUFS needs -4.2 dB.
- Measure it. Drop the file above and note the reading. The line under the number already gives the gain to -14 LUFS.
- Change the gain. In your editor, raise or lower the sound by that many decibels with a plain gain or volume control.
- Watch the peaks. A lift of several decibels can push the loudest moments past the largest level a file can hold (0 dBFS) and distort them. Put a limiter set to about -1 dB at the end of the sound chain, or stop short of -14 LUFS.
- Measure again. Export the file and drop it here to confirm the new reading.
ffmpeg's loudnorm filter does the gain and the limiting in one command. In its default one-pass mode it lands near the target, not on it (on the two speech files we tried it ended at -14.6 and -14.5 LUFS), so measure the result here.
ffmpeg -i input.mp4 -af loudnorm=I=-14:TP=-1 -ar 48000 -c:v copy output.mp4
What Burncaps does for you
Clips are levelled to -14 LUFS in the Burncaps editor. Each clip's sound is measured with the meter on this page, lifted by up to about 18 dB or lowered by up to about 6 dB to reach -14, and a look-ahead limiter keeps sample peaks under -1 dBFS. The captioned whole video keeps its sound as recorded and is not levelled, so check that file here if you need it at a level.
What this checker opens, and where it stops
| Topic | What the page does |
|---|---|
| Length | Up to ten minutes of sound, the same as the Burncaps editor's whole video. A longer file is turned away before its sound is read, because the whole sound is held in memory while it is measured: about 23 MB a minute for stereo. Trim it to the ten minutes you want to check. |
| File size | Up to 1.2 GB on a computer and up to 250 MB on phones. This page reads the whole file into the browser's memory, and 250 MB is the most the Burncaps editor reads whole on a phone. |
| Formats | Any video or audio file your browser can play and decode. We tried these in Chrome on a Mac on 3 November 2026 and each one opened: MP4 and MOV with AAC sound, WebM with Opus sound, M4A, MP3, WAV, FLAC and Ogg Vorbis. We did not test Safari, Firefox or a phone. A file with no sound, or in a format the browser cannot decode, gets a plain message and no number. |
| Channels | Mono is measured as one channel and stereo as two, as the standard says. A file with six channels is read as 5.1, with the standard's weights: the low-frequency channel is left out and the two surround channels count 1.5 dB more. Any other number of channels above two is measured on its first two. |
| What it measures | One number: the integrated loudness of the whole file. It does not draw loudness over time and it does not measure true peak or loudness range; a loudness meter in your editor, or ffmpeg's ebur128 filter, does. |
| Accuracy | On 15 test files in Chrome on a Mac (a test tone, speech in mono and in stereo, a music-like mix, a 5.1 file, a ten-minute WAV, a ten-minute MP4 of 1 GB, and the same speech as MP3, FLAC, Ogg, WebM, MOV, WAV, M4A and a WebM video) the readings matched ffmpeg's ebur128 filter to within 0.05 LU. The browser turns every file into 48 kHz sound before it is measured. |
How to check that your file is not uploaded
- Open the network tab. On a computer, press F12 (or Option and Command and I on a Mac) in your browser and choose Network.
- Clear it, then drop the file. The list shows every request the page makes while it works.
- Look at what was sent. The page's own files load before you drop anything. After the drop, nothing carries your file, because the page reads it from your device, decodes the sound there and measures it there. You may see requests to an address that starts with blob: those are the page reading your file from your own device, not a server. Caption generator with no video upload shows the same check for the Burncaps editor.
Then caption it, or cut the clips
Burncaps burns animated word-by-word captions into a talking video, and finds the best moments of a long recording as ranked, captioned 9:16 clips whose sound is levelled to -14 LUFS. Long video to Shorts and the podcast clip maker show how it works for a YouTuber's long video and for a video podcast.
What it costs
Free: 2 videos every 30 days, each with captions and up to 3 clips, no watermark, no sign-up. Then try Captions + Clips free for 7 days, no card. Captions + Clips is $29 a month for unlimited clips and captions; Captions is $9.98 a month or $49 once.
Questions, answered plainly
What is a LUFS checker?
A LUFS checker reads how loud a file sounds as one number, its integrated loudness in LUFS (loudness units relative to full scale). This one decodes your video or audio file in the browser and measures it the way ITU-R BS.1770 describes, then shows how far the reading is from -14 LUFS and from the levels Spotify, Apple Podcasts and EBU R 128 publish.
What LUFS should my video be?
There is no single right number, because each source publishes its own. Spotify adjusts tracks to -14 LUFS in its default setting, Apple Podcasts recommends around -16 LKFS with a tolerance of 1 dB either way, and EBU R 128 recommends -23 LUFS for broadcast. YouTube's Help gives no level. Burncaps levels its clips to -14 LUFS, which is our choice and not a rule YouTube prints.
What LUFS does YouTube use?
YouTube does not say. Its Help page about stable volume describes a viewer setting that evens out quiet and loud parts and gives no LUFS number, so this page gives none as YouTube's. Guides by other people report levels from their own measurements; treat each as that author's result. If you need a number to aim at, -14 LUFS is the one Spotify publishes for its default setting and the one Burncaps uses for clips.
How do I get a video to -14 LUFS?
Read its loudness here, then work out the gain you need: -14 minus the reading. A file at -19.3 LUFS needs +5.3 dB, and one at -9.8 LUFS needs -4.2 dB. Apply that gain to the sound in your editor, keep the loudest moments from clipping with a limiter set to about -1 dB, export, and drop the new file here to check it. In Burncaps, clips are levelled to -14 LUFS for you.
Is my file uploaded?
No. The page opens your video or audio file from your own device, decodes its sound there and measures it there, and the file is never sent anywhere, which you can see in your browser's network tab on a computer. The page sends only anonymous step counts, such as that someone visited, never anything from the file (see the privacy policy).
Which files open, and how long can they be?
Any video or audio file your browser can play and decode, up to ten minutes of sound, and up to 1.2 GB on a computer or 250 MB on phones. Longer or bigger files are turned away so the tab does not run out of memory: the sound is held in memory while it is measured, about 23 MB a minute for stereo.
Does it match ffmpeg or my editor?
On the 15 test files we tried, this page's readings matched ffmpeg's ebur128 filter to within 0.05 LU. Meters can differ by a few tenths of a unit when a tool resamples the file differently or follows an older revision of the standard, so compare readings made with the same meter.
Does Burncaps level the sound of my video?
Clips, yes. Each clip's sound is measured with this same meter and brought to -14 LUFS, lifted by up to about 18 dB or lowered by up to about 6 dB, and a limiter keeps sample peaks under -1 dBFS. The captioned whole video keeps its sound as recorded and is not levelled.
Burncaps facts, checked 3 November 2026
What it is: a browser tool that burns animated word-by-word captions into a talking video, or finds the best moments of a talk, podcast or interview and gives them back as ranked, captioned 9:16 clips.
Price: free for 2 videos every 30 days, each one recording with its captioned video and up to 3 clips, no mark and no sign-up; then the free 7-day Captions + Clips trial, no card (your email only); then Captions + Clips, $29 a month, gives unlimited clips and captioned videos, or Captions, $9.98 a month or $49 once, gives unlimited captioned videos. Captions paid once is not a subscription.
Privacy: the video never leaves your browser. The sound goes only to our speech service, on a phone unless you switch it off, on a computer only if you choose it. Because the video never reaches us, we cannot keep it or train AI on it, and we train no AI on anything you make.
Files: MP4 or MOV in, MP4 out. Captions on the whole video: up to ten minutes. Clips: up to three hours, on a phone or a computer. SRT, VTT, ASS and text files are free without limit for recordings up to ten minutes; a longer recording, up to three hours, gives its script and those files (the first ten minutes free, all of it as one of your free videos, in the trial or with Captions + Clips or Captions) and its clips (every one found and shown before you sign up; up to 3 from each free video exported free, every one in the trial or with Captions + Clips).
Clips: about one clip for every two minutes of talk, up to 30, ranked, the ones we would post first circled, each showing the words it opens and ends on and the reason it was chosen; each cut to 9:16 with ums and dead air removed, an opening card and captions, framed on whoever is talking. Every clip of the whole recording is found and shown, free and with no sign-up; each free video exports up to 3 of them, and the 7-day trial and Captions + Clips export every clip, unlimited.
Languages and styles: captions in the language spoken, twelve Indian languages heard on your device, translation into 59 languages, 60 caption styles.
After it listens: correct any word (one click changes it everywhere), add or cut words, one to six words at a time, position, size, text and highlight colours, and names this browser remembers, all free and without listening again.
Made by: Jordan Labs Ltd, UK company no. 17358646.
Against other tools: sixteen caption tools compared, from the vendors' own pages.