Registers · what the microphone can hear

Does vocal range count head voice?

Yes, on the same rule as every other note: hold it steadily for 2.0 s and it is entered, head voice or chest. A browser cannot hear which register you are in — it hears pitch, and pitch is all a microphone carries — so the honest answer is the same one falsetto gets. What the result does instead is separate what you held from what you only reached, so a head-voice top you can genuinely sustain reads differently from one you can only touch. If you want the chest-only number, run it twice and stop before you flip. Neither number is the real one; they answer different questions.

For scale, here are the 16 singers in the catalogue whose top sung note reaches C5, the top of the tenor band. What register any of them was in is not something a recording tells you, so the table names the note and stops there.