Free Audio & Video Tools
Convert, trim, compress and transcribe media — the heavy lifting happens on your own machine.
Media files are the awkward ones. They are big, the formats are a maze of containers and codecs, and the moment you search for a converter you are three ads deep in something that wants a 400 MB upload and an email address. These tools skip all of that by running FFmpeg compiled to WebAssembly directly in your browser — the same engine the professionals use, executing on your CPU rather than someone else's.
Changing format. MP4 to MP3 is the workhorse: pull the audio out of an MP4, MOV, MKV or WEBM when all you actually wanted was the soundtrack, the interview or the lecture. The Audio Converter moves between MP3, WAV, OGG, M4A and FLAC — useful when a DAW, a phone or a car stereo insists on one specific format.
Changing length and size. Trim Video cuts a clip to a start and end point without re-encoding, so it is nearly instant and loses no quality. Compress Video is for the file that is 40 MB too large for the upload limit, with honest High/Medium/Small presets. Video to GIF turns a few seconds of footage into the loop you actually wanted to send.
Turning speech into text. Two tools cover this. YouTube Transcript pulls the existing captions from a video, with timestamps, as TXT or SRT. Audio to Text Transcription is the exception to our no-server rule and we say so plainly: speech recognition needs a model too large to ship to a browser, so that one file is processed on our own infrastructure and then discarded. Every other tool on this page keeps your media local.
The musicians are catered for too — the Guitar Tuner listens through your microphone and the BPM Tapper & Metronome finds a tempo by tapping, neither of which records or transmits a thing.
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Audio & video FAQ
Why is video conversion slower here than on other sites?
Because your computer is doing the work, not a server farm. A site that converts a 500 MB video "instantly" has uploaded it, encoded it on rented hardware and given you a link — which means a copy of your video now exists somewhere you do not control. ZillaKit runs FFmpeg in WebAssembly on your own CPU: a little slower on long files, but nothing is transmitted, and there is no queue and no upload wait.
Is there a file size limit?
There is no artificial cap, but there is a practical one: the browser holds the file in memory while it works. Clips up to a few hundred megabytes are comfortable on a modern laptop; a two-hour 4K recording will strain any tab. If a large job stalls, trim it into sections first, close other tabs, and use a desktop browser rather than a phone.
Can I get subtitles for a video that has none?
Yes — use Audio to Text Transcription and export as SRT, which drops straight into YouTube, Premiere or VLC. If the video already has captions and it is on YouTube, YouTube Transcript is faster and completely free of processing time, since it simply fetches the caption track that already exists.