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Tools
Online Audio Tools
17NAS Online Audio Tools is a free, browser-based audio editor: cut audio, convert to MP3 (96–320 kbps) or WAV, boost or normalize volume, extract audio from MP4/MOV/WebM videos, add fades and change speed from 0.5× to 2×. Everything is processed locally in your browser — files are never uploaded, and there is no sign-up and no watermark. Readable formats depend on your browser’s decoders, and files over 400 MB trigger a memory warning.
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Cut mode
Drag on the waveform to select, drag the handles to fine-tune, or type times as m:ss.mmm (e.g. 1:23.500) or seconds. When deleting a selection, the join is smoothed over 4 ms to avoid clicks.
MP3 is encoded in your browser with the LAME encoder (lamejs), so long files take a while; WAV is lossless 16-bit PCM. Browsers decode audio at a fixed 44.1 kHz here, so "Keep" exports 44.1 kHz.
Positive gain makes it louder; anything above 0 dBFS gets clipped and distorts. For "as loud as possible without distortion", enable Normalize (the gain slider is then ignored).
Choose an MP4, MOV or WebM video and your browser decodes its audio track directly. Trim it if you like, then export as MP3 or WAV. The video frames are not processed or uploaded.
MP4 with AAC audio decodes in all major browsers; MKV, AVI, WMV and AC-3/DTS audio usually cannot be decoded in a browser — convert to MP4 first. The whole video is loaded into memory, so keep files under about 1 GB (300 MB on phones).
Fades are applied to the start and end of the exported audio (linear). For ringtones, a 0.5 s fade in and 1–2 s fade out sound natural.
Speed is changed by resampling, so pitch changes with it (like speeding up a record). Pitch-preserving time-stretch is not available.
Choose an audio or video file first
This format uses your browser’s built-in encoder and records in real time (a 3-minute clip takes about 3 minutes). Keep this tab in the foreground.
🔒 Privacy: decoding, cutting, effects and encoding all happen locally in your browser. Your audio and video files are never uploaded to 17NAS or any third-party server, and everything is cleared when you close or reload the page.
Key facts at a glance
Price
Free — no sign-up, no watermark, no usage limits
Runs on
Any modern browser (Chrome, Edge, Firefox, Safari) on desktop or mobile; nothing to install
Input formats
MP3, WAV, M4A/AAC, FLAC, OGG/Opus; video MP4, MOV, WebM (depends on browser decoders)
Output formats
MP3 (96–320 kbps; max 160 kbps below 32 kHz), WAV (16-bit PCM); WebM/OGG (Opus) or M4A (AAC) in real time where the browser supports it
Millisecond-accurate cut/delete, −20 to +20 dB gain, peak normalize, 0–10 s fades, 0.5–2× speed (pitch changes too)
Speed
MP3 encodes at about 5× real time on a typical computer (≈12 s per minute of audio), slower on phones; WAV is near-instant; WebM/OGG/M4A record in real time
File size
No hard limit; files over 400 MB show a memory warning; aim for under 1 hour on a computer and 15 minutes on a phone
Privacy
Files are processed only in your browser and never uploaded to 17NAS or any third party
Last updated
How to use these online audio tools
Four steps: pick a file, select a part, choose a format, export. Everything runs locally in your browser — nothing is uploaded.
1
Step 1
Choose or drop a file
Click "Choose file" or drop audio or video into the dashed box — MP3, WAV, FLAC, MP4 and more.
2
Step 2
Select a part on the waveform
Drag across the waveform to mark the part to keep or delete; use the handles or type times for millisecond precision.
3
Step 3
Pick a tool and format
Switch between tabs like Convert, Volume and Fade to set MP3/WAV, bitrate and effect options.
4
Step 4
Export and download
Click "Export audio", preview the result, then hit "Download" to save it to your computer or phone.
This tool only uses your browser’s built-in Web Audio features and a lightweight JS encoder, with no server involved, so some things are browser-dependent or not possible:
Feature
Status
Notes
Open audio / video files
Browser-dependent
MP3, WAV, M4A/AAC and MP4 work in all major browsers; FLAC, OGG/Opus and WebM depend on the browser; MKV, AVI and WMA usually don’t
Cut / delete a section
Supported
Millisecond-accurate start/end; joins are smoothed automatically
Convert to MP3
Supported
lamejs (LAME) encoder, 96–320 kbps, mono or stereo
Convert to WAV
Supported
16-bit PCM with selectable sample rate and channels
OGG / WebM (Opus), M4A (AAC)
Browser-dependent
Recorded in real time with the browser’s built-in encoder: usually WebM in Chrome/Edge, OGG in Firefox, M4A in Safari
Volume boost / normalize
Supported
−20 to +20 dB gain, or peak-normalize to −0.1 … −6 dBFS
Extract audio from video
Browser-dependent
MP4/MOV/WebM usually work; MKV, AVI and AC-3/DTS audio usually don’t
Fades and speed change
Supported
0–10 s linear fades; 0.5–2× speed (pitch changes too)
Pitch-preserving speed / pitch shift
Not supported
Needs complex time-stretch algorithms that are unreliable in the browser; not offered yet
Export FLAC / ALAC
Not supported
Browsers have no built-in encoder; use WAV for lossless output
Large files / long audio
Browser-dependent
No hard limit, but decoded audio is held in memory (about 1.3 GB per hour of stereo); files over 400 MB show a warning and may fail on phones
Batch processing, multitrack mixing
Not supported
One file at a time on this page
FAQ
Are my files uploaded to a server?
No. Decoding, cutting, effects and encoding all happen in your browser; the page never sends audio or video to any server. The MP3 encoder is a static script hosted on this site and is loaded once, only when you pick MP3.
Which input formats work? Why does it say it can’t decode my file?
It depends on your browser’s built-in decoders. MP3, WAV, M4A/AAC and MP4 work in all major browsers; FLAC, OGG/Opus and WebM work in Chrome, Edge and Firefox but may fail in older Safari; MKV, AVI, WMA and AC-3/DTS usually fail. If decoding fails, try Chrome/Edge or convert the file to MP4/MP3 first.
How do I extract audio from an MP4 and save it as MP3?
Open "Video to audio", choose the MP4, optionally trim once the waveform appears, set the output to MP3 at 192 or 320 kbps and click "Export audio". The video is never uploaded.
Which MP3 bitrate should I choose?
For music, 192 kbps balances size and quality, and 320 kbps sounds close to lossless. For speech, podcasts and lectures, 96–128 kbps is enough, and switching to mono halves the size again. Converting a low-bitrate file to a higher bitrate does not improve quality.
How do I make quiet audio louder? What’s the difference between normalize and gain?
Gain raises or lowers the whole file by a fixed number of decibels; too much pushes it past 0 dBFS and it clips. Normalize finds the loudest peak and calculates the gain so that peak lands exactly on the target (−1 dBFS by default) — as loud as possible without clipping. If an export clips, the page warns you.
Can I make a ringtone with it?
Yes. Select a 20–30 second chorus, add a 0.5 s fade in and a 1–2 s fade out, and export MP3 for Android phones. iPhone ringtones need M4R: export WAV and import it into GarageBand.
Are there file size or length limits?
There is no hard limit, but decoded audio is held in memory as 32-bit floats — about 1.3 GB per hour of stereo, plus a working copy. Keep it under about an hour on a computer and 15 minutes on a phone. MP3 encoding runs in the browser at roughly 5–20× real time, so give long files a moment.
Why is the exported sample rate 44.1 kHz?
Browsers resample audio to the audio context’s rate when decoding. This tool uses 44.1 kHz (the CD standard every player supports), so "Keep" means 44.1 kHz. If you need 48 kHz (common for video) or 16 kHz (common for speech recognition), choose it in "Convert".
Is this online audio tool free? Does it add a watermark or limit usage?
Yes, it is completely free: no sign-up, no watermark and no limit on how many files you process or export. All processing happens locally in your browser; 17NAS servers never handle your files.
How long does MP3 export take?
MP3 files are encoded in your browser by the built-in lamejs encoder at about 5× real time on a typical computer (≈12 seconds per minute of audio, ≈12 minutes per hour), slower on phones. WAV export is near-instant. A progress bar is shown and you can cancel at any time. WebM/OGG/M4A are recorded by the browser in real time, so they take as long as the output.
