What loudness target is commonly used with ATSC A/85?
A common U.S. broadcast target is -24 LKFS. In this browser tool, the measured loudness estimate is shown in LUFS on the same numerical loudness scale for practical comparison.
CALM Act Loudness Checker -24 LKFS / LUFS
Analyze audio or supported video locally in your browser, compare the integrated loudness estimate with a -24 LKFS target, and see the approximate gain change needed.
Upload Audio or Video
Analysis starts automatically after you choose a supported media file.
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Load a file to check loudness
Results will appear here after the browser decodes the audio.
-- LUFS
Integrated estimate
Loudness Details
The loudness estimate uses K-weighting and gating in a browser-side BS.1770-style workflow. Peak reporting is sample peak, not true peak.
Quieter
Target -24 LKFS
Louder
Below range
Selected range
Above range
-36-30-24-18-12
What this CALM Act Loudness Checker does
This free browser tool gives a fast preflight estimate of integrated loudness for audio and supported video files. It compares the measured LUFS estimate with your selected LKFS target and reports the target difference, approximate gain adjustment, sample peak, duration, channel count, and loudness variation estimate.
Important: This is not an official legal determination and is not affiliated with the FCC, ATSC, or any broadcaster. Use it for editing and QA preflight only.
How to check loudness
Choose a media file, wait for the local browser analysis, review whether the estimate is below, within, or above your selected range, then use the suggested gain as a starting point.
How to use the gain suggestion
If the result is outside the selected range, apply the suggested level change in your editor or loudness normalizer, export again, and re-measure before delivery.
Why sample peak matters
Increasing gain can push sample peaks closer to 0 dBFS. The peak warning helps flag possible headroom problems, but it does not replace a true-peak meter.
Privacy
Supported files are decoded and analyzed in your browser with the Web Audio API. The loudness check does not require uploading your media file to the server.
CALM Act Loudness FAQ
Practical answers about -24 LKFS, LUFS estimates, sample peak, gain adjustment, supported media, and final delivery checks.
Are LUFS and LKFS the same number?
For practical loudness reporting they use the same numerical scale. ATSC A/85 commonly uses the term LKFS, while many modern audio tools display LUFS.
What tolerance should I use?
This tool starts at plus or minus 2 LU as a practical preflight range. Your broadcaster, platform, station, network, or delivery specification may require a different tolerance, so always follow the destination specification.
Does this tool certify CALM Act compliance?
No. It is a browser-based preflight estimate for editing and quality checks. It is not an official legal determination, certified loudness meter, or broadcaster approval.
What does the suggested gain mean?
Suggested gain is the approximate level change needed to move the measured integrated loudness toward your selected target. After applying gain, export the file and measure it again.
Does this measure true peak?
No. The current browser analysis reports sample peak in dBFS. Sample peak is useful for a quick warning, but it is not the same as an oversampled true-peak measurement.
Can I check MP4 or other video files?
Yes, when your browser can decode the audio track. Common audio and video formats such as WAV, MP3, M4A, AAC, OGG, FLAC, MP4, MOV, and WebM may work depending on browser codec support.
Why can this result differ from a professional loudness meter?
This is a browser-side BS.1770-style estimate and browser decoding can differ by codec, channel layout, gating details, and meter implementation. Use an approved meter for final regulated or contractual delivery.
What should I do if the audio is above target?
Reduce level by approximately the suggested gain amount, check peak headroom, export again, and re-measure. Avoid relying on a single gain change if compression, limiting, or remixing changes the program dynamics.
Are my media files uploaded to Valsolution?
No. This tool reads and analyzes supported media locally in your browser with the Web Audio API. The media file does not need to be uploaded to the server for this loudness estimate.