> ## Content Index > Fetch the complete content index at: https://soundforgepro.com/llms.txt > Use this file to discover other available public pages before exploring further. # Free Online LUFS Meter: Loudness & True Peak - URL: https://soundforgepro.com/lufs-meter/ - Published: 2026-08-25T14:29:33.000Z - Updated: 2026-09-04T21:17:48.000Z - Description: A private browser loudness check with integrated LUFS, LRA, estimated true peak, sample peak and a peak-aware gain plan. - Author: Erick Finn - Tags: Mastering, Audio Tools Drop a finished WAV or another browser-decodable audio file into the meter below. The page measures the file on this device; it doesn’t upload the audio, keep its filename or send the readings to analytics. The four useful numbers are integrated loudness, loudness range, estimated true peak and sample peak. Read them together: a single LUFS value can’t tell you whether the file will cross a peak ceiling, and a peak reading says nothing about how loud the whole programme feels. Browser tool · local analysis ## Measure the file, not the guess Your audio stays on this device. The page does not upload the file or send its name and readings to analytics. **Drop an audio file here** or press Enter to choose one · mono or stereo · up to 200 MB and 20 minutes Formats depend on your browser's decoder. WAV is the safest choice for a final check. Reference Spotify Normal reference EBU R128 broadcast ATSC A/85 television Custom Target LUFS/LKFS Peak ceiling dBTP Analyze file Reset Integrated loudness**—**LUFS · gated full-file reading Estimated true peak**—**dBTP · 4× polyphase pre-check Loudness range**—**LU · programme variation Sample peak**—**dBFS · highest stored sample This is a practical browser pre-check, not a certification meter. Our deterministic tests matched FFmpeg's integrated loudness within 0.1 LU; the true-peak estimate can read about 0.4 dB lower on difficult broadband material. Verify regulated or final delivery in a conforming production meter. ## How to measure LUFS without uploading the file 1. **Choose a mono or stereo file.** PCM WAV is the safest final-check format; compressed formats work only when your browser can decode them. 2. **Select a reference.** Use Spotify Normal for a playback comparison, EBU or ATSC for their specific delivery contexts, or enter a custom loudness and true-peak ceiling. 3. **Press Analyze file.** The browser decodes the full programme and runs the loudness calculation in a local worker. 4. **Read the gain plan.** If the LUFS target needs more gain than the peak ceiling allows, the meter says so instead of pretending that normalization is a one-number fix. ## Read the four numbers in this order | Reading | What it answers | What it does not answer | | ------------------------- | ------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Integrated LUFS | How loud the complete gated programme measures | Whether inter-sample peaks cross a delivery ceiling | | Estimated true peak, dBTP | How high the reconstructed waveform may rise between stored samples | Whether the track is dynamically healthy or musically balanced | | Loudness range, LU | How widely short-term loudness varies across the programme | Whether a particular genre “should” be more or less dynamic. EBU R128 does not recommend LRA for programmes shorter than one minute because there are too few short-term data points. | | Sample peak, dBFS | The highest amplitude actually stored in the file | The inter-sample peak after reconstruction or lossy encoding | The compact result footer also reports short-term maximum and momentary maximum. They flag the loudest three-second and 400 ms windows; neither replaces the full-file integrated reading. The measurement follows the gated programme-loudness method described in [ITU-R BS.1770-5](https://www.itu.int/rec/R-REC-BS.1770-5-202311-I/): K-weighted energy is measured in overlapping blocks, then very quiet material is excluded by absolute and relative gates. That is why long silence at the head or tail does not simply drag the integrated result down like an ordinary average. ![Browser LUFS meter results for integrated loudness, true peak, loudness range and sample peak](https://storage.ghost.io/c/af/4b/af4b05d4-2e0b-4edc-8378-1e2a62fecc70/content/images/2026/08/lufs-meter-results-real-v1.webp) The same deterministic test file in the working browser meter: loudness, peaks and the gain plan remain separate. ## A target is a reference, not a grade The presets deliberately cover only numbers we can tie to current primary sources. They are not interchangeable. For spoken-word delivery, use the publisher's or host's stated target instead of borrowing a music or broadcast preset; the [podcast loudness standard](https://soundforgepro.com/podcast-loudness-standard/) guide covers common stereo and mono targets, true-peak checks, and export verification. - **Spotify Normal** is a playback-normalization reference of −14 LUFS. Spotify also advises keeping true peak below −1 dBTP for masters at or below that level and below −2 dBTP for louder masters, because lossy encoding can add peak energy. Those details are in [Spotify’s loudness-normalization guidance](https://support.spotify.com/artists/article/loudness-normalization/). - **EBU R128** uses −23 LUFS and a −1 dBTP maximum permitted true peak in the production and distribution context covered by the [current EBU recommendation](https://tech.ebu.ch/publications/r128). - **ATSC A/85** uses −24 LKFS absent metadata and a −2 dBTP ceiling in its television delivery context. As of September 5, 2026, ATSC lists A/85:2026-07, approved July 8, 2026, on the [ATSC A/85 technical page](https://www.atsc.org/atsc-documents/a85-techniques-for-establishing-and-maintaining-audio-loudness-for-digital-television/). LUFS and LKFS are equivalent units here; the different label follows the standard’s wording. None of those numbers can decide how much compression, limiting or musical density a master needs. If a mix sounds right at −10 LUFS and will be normalized at playback, the useful question is what the platform will do and whether the dynamics survive, not whether a green badge appears. ## When the gain plan says “peak-limited” Suppose a file measures −18 LUFS with an estimated true peak of −2 dBTP, and the selected reference is −14 LUFS with a −1 dBTP ceiling. Loudness asks for 4 dB of gain, but the ceiling allows only 1 dB. A plain gain change cannot satisfy both numbers. The remaining 3 dB is not “free normalization.” It would require a limiter, compression, clipping or a different mix decision. The meter reports that conflict but doesn’t process the file, because choosing how peaks are controlled is an audible mastering decision. ## What we verified—and where this meter stops Before using the measurement core here, we checked deterministic 44.1 and 48 kHz fixtures against FFmpeg’s `ebur128` filter: steady tones, low-frequency weighting, broadband noise, gated dynamics, correlated and anti-phase stereo, silence and inter-sample-peak signals. | Metric | Largest observed difference in our fixture set | How to use it | | ------------------- | ------------------------------------------------------ | --------------------------------------------------------------------------------------- | | Integrated LUFS | Within 0.1 LU | Suitable for a practical local loudness check | | Loudness range | Within 0.1 LU | Useful for programme-level comparison | | Estimated true peak | About 0.4 dB lower on the hardest broadband-noise case | Use as a pre-check; verify regulated or final delivery in a conforming production meter | Version one accepts mono and stereo programmes up to 200 MB and 20 minutes. It relies on the browser’s audio decoder, so extension support isn’t universal. It won’t certify a broadcast master, inspect encoded-platform output or replace listening after gain and dynamics changes. ## Check the same file in Sound Forge If Sound Forge is already in your workflow, use this browser meter as a quick independent read, then repeat the measurement in the editor before export. Our [Sound Forge LUFS, R128 and true-peak guide](https://soundforgepro.com/sound-forge-loudness-meters/) shows the current Channel Meters, separate Loudness Meters window, EBU/ATSC presets and loudness-log route. That separation matters for search and for the reader: this page measures a file now; the Sound Forge guide explains how to monitor, preset and log loudness inside the desktop application. ## Frequently asked questions ### Is my audio uploaded to SoundForgePro? No. The browser reads and decodes the selected file locally. The tool does not send the audio, filename or measured values to our server or analytics. ### Which file formats does the LUFS meter support? It supports audio formats your browser can decode. PCM WAV is the most dependable choice; MP3, AAC/M4A, OGG, FLAC and AIFF availability can differ by browser and operating system. ### What is the difference between LUFS and dBTP? Integrated LUFS describes gated programme loudness over time. dBTP describes the estimated highest reconstructed peak between samples. One is a loudness measure; the other is a peak-safety measure. ### Should every song be mastered to −14 LUFS? No. −14 LUFS is Spotify’s Normal playback reference, not a universal mastering instruction. Musical density, dynamics, genre, release context and true-peak headroom still require judgement. ### Why can true peak be higher than sample peak? A digital-to-analog or lossy-codec reconstruction can form a waveform crest between stored samples. Oversampled true-peak estimation looks between those sample points; an ordinary sample-peak meter does not. ### Can this tool normalize or download a corrected file? No. It measures and calculates a peak-aware gain plan but does not alter the audio. Limiting or compression is an audible decision that should be made in an editor or mastering chain and checked again afterward.