Make a video black and white
Desaturating means recolouring every frame, which is a filter and therefore a timeline job. The full editor has it with live preview and an adjustable strength — this page takes you there.
Result right hereDrop a video here, or click to choose
MP4 · MOV · MKV · WebM · audio · images · subtitles · ZIP
Removing colour sounds like the simplest possible edit, and in a sense it is — but it still touches every pixel of every frame, which puts it with the filters.
In the editor it is one of the 26 filters, with a strength control so you can stop partway if you want a faded look rather than full monochrome.
Live preview means you see it on your own footage before committing.
FAQ
Can I go partway?
Yes — the strength control lets you desaturate as far as you like.
Does it make the file smaller?
Slightly, since there is less colour information, but not dramatically.
Can I keep one colour and drop the rest?
That is selective colour, which is beyond what the filters do here.
Can I apply it to part of a clip?
Split first, then filter the piece.
Is it free?
Yes.