How to Convert Video to MP3 in Your Browser with Untitled
Reviewed by the OnlineFree.app team · Updated
Key points
- Untitled converts your own MP4, MOV, WEBM, M4A, WAV, OGG or MP3 files to MP3 entirely inside your browser.
- At 192 kbps, expect roughly 1.44 MB of MP3 per minute of audio; 320 kbps is about 2.4 MB per minute.
- Nothing is uploaded: decoding uses the Web Audio API and encoding uses the lamejs encoder locally.
- The tool cannot fetch YouTube or any streaming URL — you must supply a file you already own.
- Keep the tab open during conversion; closing it cancels the encode and you lose the result.
How do you turn a video file into an MP3?
Drop your file onto Untitled, choose a bitrate, and tap Convert to MP3 — the decoding and encoding both happen inside your browser tab, and the download button hands you a real MP3 named after your source, such as clip.mp3. There is no upload step, no account, and no watermark.
The file types we accept are MP4, MOV, WEBM, M4A, WAV, OGG and even MP3. Video containers work because the browser decodes the audio track and discards the picture; MP3 input works too, though it means re-encoding audio that was already compressed. One file per run: the drop zone is the whole job, which is why the settings strip sits collapsed below it.
The flow is five steps. Open the page, drop or pick one file, adjust bitrate (128, 192, 256 or 320 kbps), sample rate (44100 or 48000 Hz), mono or stereo, and optional trim points, then press Convert. When it finishes, the result card shows duration, bitrate, channels and output size in MB, plus a badge like "78% smaller than source" when the original size is known.
Under the hood it uses the Web Audio API to decode and the lamejs encoder to write MP3 data, all client-side. That is the same local-processing approach we use for the Product Photo Background Remover: your bytes never leave the device.
Which bitrate should you choose?
192 kbps is the default and a sensible middle for most speech and general listening. The size math is simple: kbps × 1000 ÷ 8 gives bytes per second, so 192 kbps is 24,000 bytes per second, or about 1.44 MB per minute of audio.
For reference, 128 kbps is roughly 0.96 MB per minute and suits voice notes, interviews and lectures. 256 kbps lands near 1.92 MB per minute, and 320 kbps sits at about 2.4 MB per minute — pick 256 or 320 when the source is music or when you plan to edit the MP3 further.
Sample rate matters less than people expect. Choose 44100 Hz for CD-derived music and 48000 Hz when the audio came from video; a mismatch just means one extra resampling pass, not a broken file. Switching to mono roughly halves the data, which is useful for spoken word but collapses the stereo image on music. MP3 is a lossy format (ISO/IEC 11172-3), so re-encoding an M4A or MP3 source at a low bitrate compounds the loss — go higher on those inputs.
Trim seconds, not megabytes
The trim fields take seconds, not percentages. Start defaults to 0 and end is auto-filled with the detected duration, and the tool validates that 0 ≤ start < end ≤ duration, so you cannot ask for audio that does not exist.
Trimming before encoding saves time as well as size, because the browser only encodes the range you asked for. A 10-minute recording trimmed to the 90-second passage you actually need produces a file around 15% of the full-length version at the same bitrate.
The common mistake is typing an end value past the real duration — usually from misreading minutes as seconds. Read the auto-filled number first, then adjust. Trimming is also the cleanest way to remove a count-in, a podcast intro or trailing silence instead of editing it out later.
Why pasting a YouTube link does nothing
There is no URL field in Untitled, and that is deliberate. This tool has no server-side downloader, no yt-dlp, and no way to fetch media from a streaming address; ripping streams carries terms-of-service and legal risk, and a small CPU-only box is the wrong place to attempt it.
What we deliver instead is the underlying intent: free, instant MP3 conversion of a file you already own. Screen recordings, camera exports, voice memos, and downloads from platforms that offer an export button all work. Several creator dashboards let you download your own uploads — check the rights you have before converting anything you did not create.
As of 2026, we still see people searching for "YouTube to MP3" when they really want a 2 MB audio file for a commute. If you have the file, this page is the fastest route to it.
Quality checks and honest limits
Encoding runs on your device's CPU, so speed depends on your hardware. A three-minute song usually finishes in a few seconds on a laptop and longer on a mid-range phone. Keep the tab in the foreground; closing it cancels the encode and you lose the result.
Files above 80 MB trigger a warning because browser memory is finite, and very long recordings can stall a mobile browser. If that happens, split the source or trim it first.
After conversion, check the summary row rather than trusting the download blindly: duration, bitrate, channels and size should match what you selected. The savings badge compares the MP3 against the original container, which also carried video, so a large percentage is normal. Untitled is one of a set of browser-first tools on OnlineFree.app, and for anything you care about long-term, keep the original WAV or MOV as your master and treat the MP3 as the shareable copy.
Frequently asked questions
Is Untitled free to use, and does it add a watermark to the MP3?
Yes, Untitled is free and adds no watermark, no account requirement and no export limit. You open the page, convert one file, and download the MP3 directly. The trade-off is that conversion happens on your own device, so speed depends on your hardware rather than on a paid server.
Does my video file get uploaded to a server when I convert it?
No. Untitled decodes your file with the Web Audio API and encodes the MP3 with lamejs inside the browser tab, so the bytes never leave your device. That also means there is no server-side queue: your conversion speed is your device's speed, and closing the tab cancels the job.
Can I paste a YouTube link into Untitled and get an MP3?
No. Untitled has no URL input and no downloader of any kind; it only converts media files you already have on your device, such as MP4, MOV, WEBM, M4A, WAV, OGG or MP3. Anything you own or have the right to convert works, including screen recordings and platform exports of your own uploads.
What bitrate should I pick for music versus speech?
Use 256 or 320 kbps for music and 128 kbps for voice notes, interviews and lectures, with 192 kbps as a balanced default. At 192 kbps you get roughly 1.44 MB per minute; at 320 kbps it is about 2.4 MB per minute. Higher bitrates matter most when the source is already compressed.
How big will the MP3 file be compared with my original video?
Much smaller, because the video track is discarded. Roughly, size in MB equals bitrate × seconds ÷ 8000, so a 3-minute track at 192 kbps lands near 4.3 MB. Untitled shows the exact output size plus a badge comparing it with the source file when that size is known.