A key with a physical mechanism behind it that resists the finger, so playing takes effort and dynamics come from that effort. It is the property that separates a digital piano from a keyboard, whatever the key count.
Why it matters
Control over volume and articulation on a piano comes from the interaction between finger and mass. Remove the mass and the hand has nothing to work against.
What graded adds
A graded action varies the weight across the keyboard — heavier in the bass — which is how an acoustic piano behaves.
The practical test
Press a key very slowly. On a weighted action there is resistance the whole way down; on an unweighted one there is a spring and a switch.
The questions players ask
Is it the same as touch-sensitive?
No. Touch sensitivity changes the volume according to how hard you play; weighting changes how hard playing is. An instrument can be touch-sensitive with completely unweighted keys.
How do I tell from a listing?
The word "weighted" or "hammer" appears, or it does not. Where it is absent, assume the keys are not weighted.
Last reviewed 2026-08-19