Thanks for your quick response Aditya.

I've read that too and unfortunately don't find anything on that page that answers my question.

Hmmm...

Either the question was not clear enough or I've been smoking the carpet...  :O)

Let's try to formulate it otherwise...

With somefont defined through \definetypeface[somefont][...]

style={\switchtobodyfont[somefont,huge]} gives a compile error,
only, for example, style={\switchtobodyfont[somefont,14pt]} works

like in \setuphead[chapter][style={\switchtobodyfont[somefont,14pt]}]

I don't want to manually input some pt size but, for example, the \tfc or huge corresponding pt size.

Therefore I'm looking for

- the ConTeXtMagicCommand to convert
\ConTexTMagicCommand[\tfc or huge] to "\tfc or huge size expressed in pt"

or

- some other ConTeXtSuperMagic trick to display the chapter heading in somefont and \tfc or huge size

I guess I could \chapter{\tfc chaptertitle}, however I'm looking for something more generic so I only have to input chapter{chaptertitle}.

Cheers,
Alan