- Is my video uploaded anywhere?
- No. The whole conversion runs inside your browser tab. The page reads the MP4 from your disk in small pieces, decodes the audio with your browser's built-in media decoder, and encodes the MP3 on your device. You can open your browser's network tab while it runs and watch — the video isn't sent to any server. That's also why there's no upload wait: a 1 GB video starts converting the moment you click.
- Which bitrate should I pick?
- Match it to what you're saving. For speech — lectures, interviews, meetings, podcasts — 128 kbps is plenty and keeps files small. For music, 192 kbps is the sweet spot most people can't tell apart from the original. Choose 320 kbps if you want the most headroom and don't mind a bigger file. One catch: the audio inside most MP4s is already compressed (usually AAC at 96–256 kbps), so picking a bitrate far above the source makes a bigger file without restoring any detail that was already lost.
- How big will the MP3 be?
- MP3 size is bitrate × length, so you can work it out before converting. Each minute of audio takes about 0.9 MB at 128 kbps, 1.4 MB at 192 kbps, and 2.3 MB at 320 kbps. A 4-minute music video at 192 kbps comes out around 5.6 MB; a 1-hour lecture at 128 kbps is about 55 MB. The tool shows this estimate before you click Convert, and the real file usually lands within a few kilobytes of it (a video with embedded cover art adds the size of that image). The video's size doesn't matter — a 4K clip and a 480p clip of the same length make the same size MP3.
- Does converting to MP3 lower the audio quality?
- A little, and it can't be avoided with any converter. MP3 is a lossy format, and so is the AAC audio inside almost every MP4, so this is a lossy-to-lossy re-encode. At 192 kbps or 320 kbps the difference is very hard to hear. If you need a bit-perfect copy for editing, keep the original video or convert to a lossless format like WAV instead of MP3.
- What's the biggest file I can convert?
- Up to 4 GB and 3 hours per file. The video is read in pieces, so its size isn't the real constraint — the finished MP3 is. It's held in your browser's memory until you download it, and 3 hours at 320 kbps is already about 412 MB. For a longer recording, split the video into parts first. On phones and older laptops, very long files can also run slowly; closing other tabs helps.
- Can I paste a YouTube or TikTok link?
- No. This tool converts video files that are already on your device — it doesn't download anything from websites. If you have a video you recorded, exported, or have the rights to, save the file first and drop it in. Downloading other people's videos from streaming sites usually breaks those sites' terms and can break copyright law.
- It says my browser can't decode the audio. What now?
- The conversion uses your browser's built-in audio decoder, which was added to browsers in the last few years. Update to the current version of Chrome, Edge, Firefox, or Safari and try again. If it still fails, the video may use an unusual audio format — some cameras and newer iPhones record spatial or lossless audio that browsers can't decode yet. Exporting the video again with standard AAC audio fixes it.
- What happens to surround sound and video without sound?
- MP3 only holds mono or stereo, so 5.1 and 7.1 surround tracks are mixed down to stereo. Mono recordings stay mono, which keeps the file smaller. Sample rates of 32, 44.1, and 48 kHz carry over as they are; anything else is converted to 44.1 kHz, the CD standard. If the video has no sound track at all — a screen recording with the mic off, for example — the tool tells you right away instead of making a silent MP3.
