Why this one is different
Every other online converter uploads your file to a server first. That is why they cap you at 200 MB or 1 GB, why a long video takes ten minutes before anything happens, and why you have to trust a stranger with the recording. This page does the work in the browser tab you already have open.
Practically, that means the size of your file barely matters. The video is read in small pieces directly off your disk as it is needed, so a two-hour recording uses about as much memory as a two-minute one. What actually limits you is your own device, not a plan tier.
Pick the right output
M4A, copied is the fastest and the best quality, because it takes the audio track out of the video without decoding or re-encoding it. Most MP4 and MOV files already contain AAC audio, so this is a straight copy — it finishes almost instantly and loses nothing. Choose it unless something you own specifically needs MP3.
MP3 is the one that plays everywhere: car stereos, old players, DJ software, anything. It re-encodes, so it takes longer and loses a little quality. 192 kbps is a sensible default for speech and most music; 320 kbps if you are keeping it.
WAV is uncompressed. Use it when you are importing into an editor and want no generation loss, and expect a large file — roughly 10 MB per minute.
Cutting
Drag across the waveform to select a stretch, then remove it. You can remove several stretches; what is left is joined together in order, with no gap or click at the joins. The readout above the button always shows the length you will actually get.